I know it's not a slot 1, the fastest slot 1 celeron was a 433, everything higher is a socket 370...
there are two different socket 370 533's, PPGA, and FC-PGA..
the PPGA's probably won't O/C at all, they are maxed out
the FC-PGA's will O/C to 100 FSB, and are very stable...
533@800, 566@850, and 600@900 are commen FC-PGA Celeron o/c's
your Asus board is one of the best ever built, it's worth upgrading if any board is...
ATA 66/100 controller card, ATA 66/100 Hard drive, FC-PGA compatable Slotket, and a coppermine PIII or celeron ... will make this M/B run with the best of them