Yes, you can put any Pentium 4 or Celeronsocket 478 processor in there, including those with an 800MHz FSB onthe processor. Don't waste your time with only a faster FSB unless youjust happen to have one laying around, the performance won't improvethat much. This one
is $50 from Newegg.
Upgrading the components is not overclocking. Overclocking is when youforce the components to run faster than they are rated for. Yourmotherboard is set up to allow this, through the BIOS. Severaloverclocking features areintegrated into the BIOS, including the ability to adjust the FSBfrequency, and the Vcore, DDR, and AGP voltages.
If you choose to overclock, be prepared to make frequent changes toachieve best performance vs. stability. I would suggest upgrading yourcooling to the best you can afford as well. Your PC may lock up orrefuse to boot for no apparent reason if you overclock. Be preparedfor that and know what to do about it before you start youroverclocking career.