It supports 1000MHz Hyper Transport (2000 MT/s), so yes it does support the AMD X2 4800+ (socket 939).
Yes, it is good for gaming. Not the best board in the world for overclocking, but it is a stabe board with some nice specs. But the question is, if you are building a NEW system, why 939? I'd recommend going for the AM2 if you are sticking to AMD, or even better, a core duo system.