1) Boards based on the 975X chipset, available for sale right now, are NOT Conroe compatable, nor will they be with just a BIOS update. The reason why is that the current boards all have a PWM buck controller that does not support VRM revision 11. At the very least a small revision to the board will need to be made along with a new BIOS. End of story.
2) 965X boards, available for sale soon, will all be Conroe compatable. These are being designed to support Conroe from release. They will most likely arrive in market before comparable 975X boards and well before Conroe is available to the public.
3) If you plan on running Conroe later this summer. DO NOT buy a 975X board now with the hope that a BIOS will be made that makes your Conroe drop-in compatable. Now, if you are buying a 975X board for other reasons, knock yourself out.