If you do still want to go ahead with overclocking, then you will need to know how overclocking affects the speed at which your RAM runs at. You will also need to know how to change the voltages at which your CPU and RAM runs at. You will then have to set up a spread sheet to calculate all your options, pick the ones you want to try. Then.. try them. Sometimes you can overclock a CPU 20%, but not 10%. Sometimes you might be able to get a substantial overclock of the CPU, but in order to do so, you have to set your RAM to a much lower speed.. Which is might be undesirable.
Before doing all of this though, I suggest you do some research on your CPU to see how well it overclocks. Also, look at your motherboard to see how well that works for overclocking. The new Intel conroes and even the dual core Pentium D chips overclock very well (at the cost of a lot of heat and lots of electrical usage, but the Pentium D's are very inexpensive now). The dual core AMD's overclock well too, but not as well a Intel's conroes. A recent price drop has put lower end AMD dual cores on par with the prices of the Pentium D's though. At one time, the dual core AMD opteron 165 was the overclocking king (it didn't require registered RAM, had a high level of L2 cache, was cheap in comparison to everything else and could be nearly doubled in clock speed for most people without even changing the stock fan, so it worked exceedingly well for home gaming rigs). A lot of Asus boards are great for overclocking, but a cheap MSI board probably won't even let you. After you find out how well your CPU and motherboard overclocks, then it's up to you if you want to void your warranty for the gain in speed and also at the cost of trying a lot of different combinations. Also keep in mind that if you overclock, you will shorten the life of the chip as well.
Edit: Oh, one more thing. When overclocking, you could get lucky and get a CPU that overclocks extremely well, or you might get unlucky and get a chip that refuses to overclock at all. It's pretty random, but chances are with a conroe chip or an opteron 165, you will be able to perform a substancial overclock.