Well, are you putting in a replacement card or are you adding an additional card?
Either way, I'm pretty sure you won't have to do anything with the driver. NVIDIA's driver is a one-size-fits-all kind of thing and the only time you need to reinstall it is when you change your kernel (or it just craps out on you).
That's only it theory though, I've never done it. Worst case scenerio is that you have to reinstall the driver. No biggy.
You'll probably have to change the XF86Config file though.
Here's a little HOWTO I think would be helpful:
http://www.linux-gamers.net/modules/...p?articleid=31
--the dudEMAN