Making a 2d AI system for a game.get from point A to B, how to?

I'm developing a simple shooter game for the iphone and I have been trying to figure out how to make my bot move from point A to point B given that there are objects in a way. Anyone can point me to a source that could help me achieve this? I'm using Box2d for my physics.

Http://en.wikipedia.org/wiki/Pathfinding