I'm afraid you won't have a lot of luck overclocking that board. While most recent Intel chipsets can be overclocked, Intel house-brand boards prohibit increasing the FSB speed or any of the voltage settings.
There is a program that tries to overclock through Windows, but frankly I haven't seen good results with it. I don't encourage even experimenting with it in your case because your memory is already choking your system performance. PC133 SDRAM is several generations behind the performance of your processor. Increasing the processor speed is only going to make matters worse. Your board also has onboard graphics and sound, and those often become unstable when overclocked.
Your Celeron is a current Socket 478 chip, and you could carry it onto a new system if you want to experiment with overclocking. But I'm afraid that is what you'll have to do. Sorry for the bad news.