To overclock an E6600 to 3000MHz you will need to raise the frequency by 600MHz. To do this, navigate to where ever you have access to changing frequency settings in your BIOS. Once there, set your FSB:Memory to "Linked". This should open up your ability to change your QFSB. Raise that QFSB until the total frequency of the processor is 3000MHz. You will most likely need to raise the vCore to the next whole number (i.e. from 1.31v to 1.4v to be safe).