I have recently rooted and wiped my phone, installing the KaosFroyo ROM.
I also installed setCPU but not sure where to go next with it. How do you run it?
Bring up the app from the icon in your app drawer and press it.
It'll poll for su permissions, which you need to allow.
Once done, it'll show you a list of possible setting/device options; press the "automatic detection" button.
Be ready to quickly move the max slider to the left, as it is often maxed out by default and can freeze your device.
Set the main max and min to a level such as 710/528 or so..
..go to profiles and set at least a sleep profile of around 245/245.
Read around about experiences with it a bit.. your settings and mine or his or hers won't necessarily garner the same performance and results. For example, I have my Kaos v30 set at 748/748 in the main settings.
I'd take a few days of operation before deciding to allow for the "on boot" check box to be enabled. Watch for heat and jerky movement or crashes, etc. Tweak the main settings down if those things begin to show themselves.