AMD® Socket AM2+ Phenom™ FX / Phenom X4 / Phenom X2 / Athlon™ X2 / Sempron™
AMD Socket AM2 Athlon 64 X2 / Athlon 64 FX / Athlon 64 / Sempron
AMD Cool'n'Quiet™ Technology
*Support CPU up to 95W

Didn't look @ power.

Actually the M3A was originally advertised as a 125W board, it wasn't until later that Asus decided to make it one of their "Green" boards that they simply modified it's compatible CPU's list to list only 95 watt TDP and lower chips. It still has the power to support the 125 watt processors.

Should still work, from what I'm reading.
Other posts say that provided you're running a BIOS revision 1102 or newer for the M3A, it should work. Might just want to poke around and read some to be sure. One post for example said that you shouldn't try to overvolt a 940 on a M3A (not that you would) because the voltage selected by autoconfiguration for the 940 isn't even an available option when manually setting voltage - the autoconfigured voltage fell outside the available range for manual config. Anyway, looks like the prognosis is that it's unsupported, but ought to work.

Edit: I vote just put it on there and see what happens. If you let all the smoke out of the CPU, get a new one

Nope this isn't a thread asking if they work together.

It's one stating that they do. I'm running a Brand new PII 940 Black Edition on my old M3A with an AMD 770 / SB600 chipset using the 1102 Beta Bios and it's running just fine. Even recognizes the processor in the bios and CPU-Z. So anyone with this board that are wondering if they can upgrade to the Phenom II. Go for it, just be sure to get the 1102 Bios before you install it.