No prob...
1) Make sure everything's at stock speeds...
2) Go into the BIOS, to Advanced Settings I guess (it could be in the Cell Menu as well), and set your RAM speed to 166MHz (from the default 200MHz)...
3) Go into the Cell Menu, and start upping your "processor frequency"... Do this 10MHz a time... After having upped it, save your settings, reboot, go into Windows, and let Prime95 run... If it appears to be stable (let's say after a minute of 5, because normally it'll fail right away), then you can proceed... If not, up your voltage (Cell Menu) a tiny bit (that should be +3.3%, no?) and check again...
Do this until you have reached 240MHz... With that HTT, your processor will run at 2.64GHz... Check your RAM speed, and it should say 200MHz... Load Windows and let Prime95 run for a long period (12+ hours is advised) to ensure it's completely stable... BTW, open CoreCell and keep an eye on the temps as well...
EDIT: Let Prime95 run with Large FFT's, this creates the most heat...