Custom PC

Hey, i'm about to build a custom pc, and i just need to know what crossfire motherboard(s) would go (work) with a AMD AM2 Athlon 64 6000+?

I've had a few searches few that results are pretty confusing.

+I dunno if to go with a Intel or AMD, in a test i saw intels core 2 was faster, but i wanna be on the eco side.

Intel is best for running lots of Apps. at once and AMD is more better at playing games. Those AM2's are nice :)