the distro has it, cd 3 iirc but itll prompt you for the right one
i think youll have to run the driver install not only as root, but with the CLI (no x server can be running)
im a n00b, so i set it to reboot without the graphical environment since i couldnt easily get it to stop x...(under one of the mandrake control center panels is a boot config thing)
reboot into the cli, login as root
run the driver installer
edit /etc/X11/xf86config4
you can do this from the CLI while youre there (i used vi, read the vi help so you can get around in it ok, not newbie freindly)
or you can use a graphical editor (open it in the kde superuser/root file manager, or startx as root so you have permission to edit it)
the line you need to edit will probably say
drivers "nv"
youll want to change "nv" to "nvidia"
save the changes and exit, then restart x
the nvidia logo will show up when X starts so you know youve done it properly