It is a primarily done in BIOS, aided with the right equipment ( your cpu, and that particilar NF2 mobo qualify most excellently ).
There is a lot of stuff on the 'net on howto, but I've found this guide to be excellent. It should be read completely to get the most out of it.
It starts with a section on cooling, and then gets into the meat of it. Cooling is a great place to start, as the major byproduct ( and potential "speedbump" ) of overclocking is heat.
Again, the guide is excellent, but should be read all the way through.
http://members.optusnet.com.au/spamzor/overclocking.htm
Hope this helps.
Scott