You'll need BIOS F8G to run the Phenom IIs... trust me about this, the Phenom II's will be much better than the first generation. More bandwidth, more cache and run a little cooler. A 600w PSU is fine, I only run a 550W Cooler Master. My specs are:
AMD Phenom II X4 965 BE Rev C3 125W OC to 3.8GHz with stock fan
Asus M4A88T-M
8GB (4x2GB Kingston DDR3-1333)
2 WD 1TB Blue Hard Drives
1 Pioneer DVD DL Burner
Video card is NVidia Zotac GTX465 (which uses like 175w I think)
Go over to the Cooler Master PSU calculator to get an idea of what you can handle. It says my current setup at max is 488w... and recommends only a 500w PSU, and I am running 550w... and I don't plan on adding anything else to my system to use power.
http://www.coolermaster.com/support/psu_calculator.php
If you don't need to upgrade in a hurry, just save for the Phenom II, they're worth it!