Welcome! For some reason you decided you want to learn how to play blitzcrank. I like sensible guides, so here let me show you what you need to know:

• This is for tank blitzcrank, don't hate, appreciate or find a different guide.
• Chalice of harmony is a must in my build, sell it late game if you must, but it is vital for mana shield.
• don't play unless you are decent with skillshots
• don't use rocketgrab on the tank especailly amumu, your team will hate you.
• You know you are doing well if the enemy decides to kill you in 2 seconds.

Pros:

• good at picking off enemies one by one safely
• pushes lanes well
• good at peeling the enemy
• great initiator
• good disrutpion
• can chase and run away

Cons:

• Quickly becomes useless in a team fight after his spells are exhausted
• mana sheild depends on current mana meaning it is possible to have a sheild for 1HP
• can get out of mana quickly.
• not good at fighting the enemy if they are highly mobile
• grabbing the enemy tank can seal your demise(Amumu getting grabbed then he uses his ultiamte)

I plan on going over this guide and adding in the other roles for blitzcrank, but for now lets talk tank!
Why do I do it this way? Well currently the new masteries are a bit daunting. However I will explain.

since he is a tank I go down defense all the way. Siege commander is a must. Blitzcrank is a very effective tower killer, and this helps that out. Think about it, increased attack speed and double damage from his skills.

I spec my summoner spells in utility because I tend to go flash&teleport on blitztank. However if you decide you want the spec somewhere else then go ahead, the utility specs aren't the best in the first place.

with blitzctrank I go with good hands and expanded mind, they both just provide too much good to pass up on him, but if you want more movement speed go ahead and spec that. But whatever you do, always fully spec up good hands. ALWAYS. With teleport and a faster respawn I have saved towers and inhibitors, even the nexus!

For runes I won't lie, I am not one to use them. However If I could Here is what I would suggest:

quintessences:
movement speed

red:
armor penetration(to utilize your overdrive and power fist)

blue:
mana regen per level(to keep your mana up for mana shield)

yellow:
magic resist per level(synergizes with his naturally scaling magic resistance)

Lets just jump into items, this is the most important part anyhow.

You are a tank in this build so don't deviate unless your team is tanky enough, or your team has so much CC that you can afford to get offensive items. that is why blitzcrank is great, he is flexible.

Core Items:

banshee's veil(amazing passive, decent Magic resist, health, mana for mana shield)
frozen heart(great aura, 2nd best armor item, mana makes mana shield better)
mercury treads(makes you tanky against magic, keeps CC from ruining your positioning)

No matter what happens, get these items. They give you stats that blitzcrank needs, and that he utilizes well.

Starting Items:

1 health potion
1 mana potion
meki pendant

keeps you in lane longer, and that mana regen is for the mana ***** which is rocket grab.

Early Game

Chalice of Harmony
boots of speed->mercury treads
catalyst the protector
glacial shroud

RUSH CHALICE OF HARMONY! /caps lock
No really. A lot of people hate it, but on blitzcrank it is extremely useful. Remember how mana shield gives you %50 of your CURRENT mana? Yeah if your total is 3000, it doesn't matter, when you have 2 mana left and you get shielded for 1 hp....chalice keeps your mana at a reasonable level and helps you spam more early and mid game. Sell it later if you want, but buy it.

obviously you can't get all of these early game, but aim for one or the other. It all depends on the team.

Middle/Late Game

banshee's veil
frozen heart
manamune

Why didn't I put tear of the goddess in early game? Because chalice took its place. As soon as you finish your early game tear of the goddess is a good choice, just don't rush manamune quite yet. You are a tank, and priority goes to tank items.

Additional options:
trinity force: Sheen proc is so good on blitzcrank. the increased movement speed, the mana, and potential to slow, all good utility for a tank as well.

Lich bane:again, sheen proc is too good. Gives some MR and AP to boot, good things he can use.

Warmogs Armor: This is something I must tell you not to get unless it is super late game, and you are getting bursted down even with mana shield. Be weary though, this is not something I would say you normally should get.

quick silver sash:free cleanse lots of MR, great choice. Don't ignore it if banshee's veil isn't enough

thornmail:
you are blitzcrank, if you do your job well enough, people on the other team will try to kill you first. If you have this with your frozen heart, you should be unstoppable to attack damage heavy teams.

Prefered:
Flash:always take this no matter what. Even nerfed, flash is good with him. Initiate in with it to silence and knock up with power fist. It also lets you over extend a little, and get into scary situations. Let mana shield come up, fight for a few more seconds, then flash out and hit over drive, you will get away unless you get double ganked, or if gangplank, ashe or twisted fate use their ultimates well.

Teleport:Blitztank is a great solo top. teleport helps those guys. Its also fun to teleport gank on a ward. with your grab and overdrive, it doesn't have to be in the fight to be effective. Also, using mana shield you can use teleport as an emergency escape. If you can take a few seconds of beating with the sheild, its a really funny move.

Other good choices:

surge:great when pushing a tower for increased attack speed, good in team fights coupled with the big electric boom you know blitzcrank for.

exhaust:your chasing power is uncanny, this makes it easier to line up a good grab, and can shut down AD cahmpions.

promote: I have yet to test it, however as a naturally good pusher, this may prove very scary.

NEVER EVER!
heal-not worth it ever, even after the buffs
revive-maybe on crystal scar, but not anywhere else.
smite-you aren't jungling
clarity-may seem good with mana shield, but really it provides only one role, improving your last line of defense(mana shield) so its not that useful.
clairvoyance-leave this for the support; no this isn't supportcrank.

Here are some random things I have picked up as I have used blitzcrank

early game, let the enemy team push your lane. In low skill games, this is easy with people just auto attacking. Before minions get in tower range try to grab an enemy champion, and let loose all you have to keep them in range of that tower and to hurt them. Makes for safe and easy kills.

singed is the anti blitzcrank. So try not grab him, he will just fling you back into his team or lane partner. Its not as bad in a solo lane, but still not ideal.

don't charge your power first before you fire a rocket grab, if you miss then you have to wait for the power fist to cooldown.

if an ally is being chased, power fist and rocket grab can be amazing at peeling them off the chase. Then to get yourself out of there power fist and overdrive can get you out of there too.

don't grab the enemy tank. I realized grabbing amumu was a bad idea early on. Never again...They generally have things that screw over the entire team.

blitzcrank is a great initiator, but don't feel bad if you miss a grab and your team runs in and dies. It isn't your fault that your AD carry decided to run in after a failed initiate, it is easy to see it fail with blitzcrank and therefore easier to point out, but really its never good to follow up on a failed initiation.

You can't grab dragon anymore, don't even try.

If the enemy has a jungler, wait behind their blue buff or red buff if they are manaless. when the buff is about to be smitable, grab it from behind, and have it aggro you. Run away and the buff creep will rapidly gain health back as it walks around again, effectivly slowing down the enemy jungler.

Grab through walls with team mates nearby for an easy kill.

with enough mana, you can kite at low health. When your allies are in position, turn and fight. Mana shield will keep you alive long enough to still do all the moves you need allowing you to kite, and help in the gank, no one else but kayle, tryndamere and zilean can do anything similar.

If your mana shield goes off in a fight, try not to stick around long if the fight is still going strong, once that shield drops you are %100 dead. The shield can deceive YOU as much as the enemy if you aren't careful.

blitzcrank was designed as a melee AD fighter. He makes a great tank in part because like all melee range fighters, he has scaling per level magic resistance. No other champions have that, not even the classic tanks.

blitzcrank once had a skin "rusty blitzcrank" but it was removed because it was just a slightly darker version of the default skin. It is the only skin that was normally available and then removed forever!

11/18/2011-guide created. I plan to add more icons for items and other things later to make skimming the guide easier.