“RivaTuner RC 12.4 was just released my friends. RivaTuner is the most powerful tweaking utility for nVidia GeForce and ATI Radeon display adapters running under Windows 98 / Windows 98 SE / Windows ME / Windows 2000 and Windows XP. The purpose of this utility is to give you access to all the undocumented features of the Detonator drivers. All versions of the Detonator drivers have a lot of undocumented registry entries. Some of them don’t affect anything, but there are some that are very useful.”
I’m definately trying out this new version. You can grab the new version here, or visit the homepage here.