Hmmmmm. the mobo sounds like it's an AM2 or AM2+ board. if it is, then the only thing preventing you from slapping any Phenom II chip in there would be the BIOS. Go to the board manufacturer's site and find out if it supports newer processors. Unfortunately major manufacturers like Dell are notoriously bad about that, however.
yea, I figured so. Was planning to upgrade to a new case, mobo, cpu, & ram in the new year anyways. But with the new AMD quad core coming out and touting backwards compatibility, I was kinda hoping it would work.
I think you're biggest problem would actually be the power requirements of the new CPU's. I have a similar board (Asus with a 6150 chipset) and it doesn't support any of the new quads.
I have heard rumours that the X4-6xx chips will work in AM2 boards though.