I have an ASUS M4A88TD-V EVO USB3.0 that is both Crossfire and SLI ready and it has more bells and whistles than any board I have used to date. It supports any AM3 chip from dual core to 6 core, as long as it is the new AM3 platform CPU. It suports the Black edition AMD chipsets and you can overclock everything on it. But, yes the AM3 mobo DO support only the AM3 chipset. Check out the specs on it here >http://usa.asus.com/product.aspx?P_ID=umllTHNRm4IGqnbL&templete=2
It is not very expensive and has plenty of room to SLI or Crossfire. I have one and know from experience.