I'm new to this whole overclocking thing, and I just overclocked my Q6600 to 3Ghz. I'm not sure wether the temp. of the cpu is too high or its just right.
CPU Q6600 - 2.4Ghz to 3Ghz OC'ed
CPU Cooler - Tuniq Tower 120 at around 2000 RPM
PSU - 520W
Vcore - 1.3
CPU Temp - 35'C Idel, 50'-60'C whilst playing a game, eg: COD4
I hope this is all the info you need. "MetalOwns" had his Q6600 at 3.2Ghz and his temp at idle was 25'C.