My name is Polson Terror, I am currently silver I only, but I'm trying to get higher on the ladder :)
This is my first guide, about my main jungler in S2 and one of my best still in S3: Nocturne.

Nocturne is a very good jungler and counterjungler, has a very good clearspeed and his ganks, if done well, can shift the game in his favor.

Pros:
- good cleartime
- good counterjungler
- ult that can catch people off-guard

Cons:
- farm dependant for items
- ult range on lvl 6 and 11 is not big
- if played poorly, he can be shut down easily

General Jungle path:

-> Blue side:
if you want to gank top or mid fast:
wraiths-red-wolves-blue-gank top-gank mid-recall
if you want to go bottom fast(hard to do succesfully though):
wolves-blue-wraiths-red-(golems)-gank bot-gank mid- recall

->purple side:
top or mid gank:
wolves-blue-wraiths-red-gank top-gank mid-recall
bot gank:
wraiths-red-wolves-blue- gank bot- gank mid- recall.

In the jungle you want to keep your Q on the ground whenever you are clearing a camp, you get extra dmg from it = faster clear. Beware of counterjunglers at your red buff (both sides) => pull the lizard in the brush and kill it while in there, so they can't sneak up on you easily.
If you see the enemy jungler going for a gank and you are nowhere near that place, go have some fun in his jungle, but make sure you are not spotted by their other lanes.

Ganking with nocturne is fairly easy to do:
Before lvl 6 you want to hit your Q on them to chase, then use your E (fear) when you catch up. This usually gets a kill, or burns a summoner/ultimate.
After lvl 6 you can use your ultimate to gank, but i DO NOT advise it. It's better to just go in a try to fear, and if they flash to use your ultimate if you're going to get the kill guaranteed.

Your ultimate can be used defensively aswell:
if you see someone being chased around the map (including yourself) you can pop the ultimate to block the vision and maybe scare them off from chasing further. You can also jump to an enemy champion to get away, but that is really hard to pull off.

Thank you for reading my guide, I will do my best to update it frequently.
As said this was/is my first guide ever, so please be gentle :P
If you want me to change/add something in here or just give your opinion on this guide, let me know in the comments ;)

Change Log:
-22/03/13: Guide started & published v0.1