I've found out about thsi software mod now, simply use nibitor to change a voltage setting from 1.05 to 1.1v, jsut eone, and poeple are getting 40mhz+ on core and 100mhz+ mroe for shaders.
Madness, definatly doing this when I get my WC'ing block for it.
NiBiTor can't do profiles and stuff, it is a BIOS editor (hence the name, Nvidia BIOS Editor). You need to use it, or another program, to save the video BIOS to a file and then edit that one. Alternatively, NiBiTor can read the BIOS and you can make changes to it and then save it as a file afterwards. You must then use a program such as nvFlash to flash the BIOS on the card. Make sure your card runs cool, voltage increases can (and most likely will) have big impacts on power consumption and temperature.
EDIT: Make a file backup of your original BIOS!!!