best bet is to find someone with a 500-700 mhz p3, 100fsb, and trade. They'll get a little faster stock chip at the higher bus speed, you may be able to get it back up to 133fsb by overclocking and achieve something close to 1ghz. But there aren't as many P3s around as a couple of years ago, so it's a bit of a long shot.
If I remember my sdram, you aren't likely to get far past 150fsb, and you'll probably need new ram to do it.