Nehalem would require... a new motherboard, new DDR3 ram sticks (yes sir... no DDR2 support. And guess what? DDR3 in tri-channel! That means you need three sticks to get the most of it!), and if you don't have one already, a new graphics card. That'll be more than $600 just for the CPU, the motherboard, and the RAM sticks. If you can't even afford this board, then don't bother... really.
And like I said, he wouldn't want to spend extra money for... another 650i board. I mean... what's the point? If he updates his BIOS, he might just be able to run the 45nm dual-core processors, anyway. So that defeat the purpose of an upgrade.

If you're upgrading, just get what "properly" supports 45nm processors (as in supporting all of them) instead of half-ass support only for specific 45nm processors. Really... that'd be more worth it as an upgrade.