You mean an overclocking program for your CPU? Or for your GPU?
If you want to overclock your CPU, you'll want to do it through BIOS. Most pre-built PCs (i.e. Dell, HP, Compaq) do not allow you to overclock through BIOS, but if you have a custom built computer, you should be able to.
If you want to overclock your GPU, get ATITool or something like that.