It's been several weeks since Asus announced that certain socket AM3 motherboards would support AMD's upcoming Bulldozer processors. Since then, we've turned up additional rumors on the nature of such support. MSI has also announced its own plans to retrofit some existing AM3 boards with Bulldozer compatibility. What follows is the general shape of the situation as we currently understand it.
P.S. My 02: it's going to be pretty similar with Phenom I / AM2 compatibility: it may work if the BIOS supports it but newer technologies related to power management and different clock domains can't work. As long as you can't power off a pin on the AM3 socket due to some missing core logic, the board can't apply power gating on the Bulldozer CPU mounted on top, right?