yes, you should! If your mobo is capable. The Q6600 is easily OC'ed to 3ghz. You only have to change the FSB from 266mhz to 333mhz. You may need to bump your core voltage a little.
Id advise you to get CPUz to determine your VID (your base voltage for the Q6600). Onc eyou have the vid, then increase the FSB in small increments. You may be able to get the Q6600 to run @3ghz without a voltage bump. This depends on the chip revision, G0 being the best, and B3 being the standard first revision. If you have G0 version you may get away without the voltage increase. For example my own Q6600 is a GO version, with a VID of 1.3v. So my base line for voltage increases start at 1.3v. To get to 3ghz, I simple changed the FSB to 333mhz, and increased the voltage to 1.312 (i think - it's been a long time!) and presto, stable and running well at 3ghz.
You can always google your Q6600 + whatever motherboard you have to get a guide for OC'ing.
Hope that helped some.
Drop me a pm if you need any other info.