Total moves possible in Chess?

Has anyone ever figured out how many games/moves are possible in chess?  There should be some easy formula right?  With a cutoff for obvious draw situations like a white king & bishop/knight chasing around a single black king.

http://everything2.com/index.pl?node=Bremermann%20Limit

That article should contain enough information (Sans the total mass of the universe) to figure it out.