Here you go. This is the motherboard that will support SLI and is the only one that will also support Conroe as of right now. I found this off of the Nvidia website. If the mobo does not say "SE" at the end (for the asus model that is) then it is not for the conroe even if it is the right socket...or thats at least my take on it. It seems the asus boards are coming in now just make sure you get the one with SE at the end.
Nope, ULi designed and produced chipsets which enable the use of SLI, even though it isn't "supported/recommended" by nVidia it works. nVidia bought ULi shortly after the chipset was released though.