6800 gt to overclock

hi i have the Aopen aeleous 6800gt and saw the review on HEXUS of it clocked up to speeds of 411 / 1100 mhz. just wondering how to do this, what program do i need? and anyone know what speed is best to overclock it to? I dont really need to overclock it yet but would like to know for when i do need to! thanks.

There is a registry hack for nivdia card which allows them to overclock called coolbits 2.0, but there is also powerstrip is good and rivatuner.