Hey this is just a short and simple guide for the Thunderbear of Awesome.
I am going to focus on Volibear as a lane champ. I feel he is a great in lane he has a amazing CC and with his passive can heal and stay in lane longer.

Pros:

He's a bear first off.
He is very hard to kill because of his passive.
Scary Jungler as he can burst out of bushes very quickly with his rolling thunder and fling you.
Can catch enemy champ very quickly with rolling thunder.
Oh and he's a bear.
Can bait enemies easily with his passive.

Cons:

Very easy to harass early game.
A slow or stun can stop a rolling thunder gank very easily.

I believe the runes to be pretty self explanatory with Volibears Frenzy and the attack speed marks he can quickly build the three stack required to bite which does ALOT of damage early game. The other runes are pretty much standard for a Tank/Jungle ill expand more on this section when I get more time.

Ill fill this in when I'm back from work.

Always take Frenzy first it will greatly help you with your laning as it stacks attack speed bonuses and lets you last hit a lot more often. Again when I am back from work I will finish this.

Exhaust is required with Volibear you can run in with Thundering Smash fling the enemy champ exhaust Sky Splitter and the enemy is suddenly in alot of trouble should be able to finish them off at low levels with Frenzy . Also I have seen a few people against the use of the summoner heal. I feel it is very needed on Volibear as combined with his passive make him excellent bait not only will his passive make his health jump quickly someone trying to gank Volibear with 35% of his health left could suddenly be facing a Volibear with near 100% of his health in a few seconds.