It's still rather doubtful that Gadhafi will be ousted. The international coalition isn't putting any boots on the ground and so far has stated they will not act as a rebel air force and will only seek to "protect civilians". So they won't be helping rebels march on to Tripoli, and the rebels sure as hell aren't going to do that themselves in the state that they're in. The most that can be said is that the rebels won't lose now. From what I've read, what most likely will happen will be a prolonged civil war via insurgency on both sides, and possibly the end result of Libya being split in two.
Who knows, Obama sitting on sidelines probably prevented a 4th world war.
First off, there's no one to fight a world war with. And second, when was the 3rd?