Most this topic in the general overclocking or cpu overclocking section and read the stickies before posting. I think most of your question would be answered after reading those stickies.
I really suggest you read up on the topic before blindly adjusting something. Or else I fear you next post will be something like: "PC don't post. have I fried my CPU?"...
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).
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