For overclocking download Rage3D from
www.rage3d.com . The program is very easy to use you shouldn't need any help.
If you want to flash the BIOS as well here is a how-to guide from the rage 3d forums.
http://www.rage3d.com/board/showthre...eadid=33695811
Keep in mind that while it works for 90% of people, there is always a chance that something could go wrong and you will be left with a dead card. But as long as you follow the directions everything should be fine.