Hey Alowishus
I am probably not well liked here for my stance on this, but I stand by it.
I've done exactly what you want to do more than once, and I've never had a single problem doing so. Infact, I don't even prep my system. Going from nV to nV is stupidly easy for the OS to cope with and it's not a trouble at all. I swapped out my Soltek NF3 250 board for an Asus A8N-E NF4 Ultra, and ran into not even a single issue. Just shut my system down, installed new mb/CPU (and a 7800GT at the time too) and away I went.. a reboot or 2 later my system was ready to rock with the latest drivers.
If I were you, I'd just make sure you install the latest drivers before you reboot, and then shut the system off as it's in reboot stage (or just shut down instead of letting the system reboot) and add the new mb. It should work perfectly.
Up to you if you want to take it farther, but you just don't have to. I'm always prepared for the possibility of format, but I almost never have any issues with a hardware swap, and my system runs stable for quite some time after. (Still running on the same install from earlier this year)
good luck w/it...