Just because the board states it's "AM3 Ready" does not make it a true AM3 Board. The New AM3 CPUs will work on all AM2+ boards, the catch is that they will only be able to run DDR2. A true AM3 board will run DDR3. That being said, there are no true AM3 boards out yet. The first line of true AM3 CPUs from AMD are set to be released on the 17th of February, as are a few AM3 boards from ASUS (perhaps even from a few other companies).
Perez, I was very close to pulling the trigger on a new system with the 940 CPU, however after learning about the upcoming AM3 launch I have decided to wait. Even if I decide not to by the AM3 system, I figure the prices on the 940 will drop a little (and maybe even the AM2+ MB I was looking at).