Off hand I can't say, but you could be at the limit of what the board can take. However, if Chaintech has support for Coppermine Pentium III's and a mulitplier of 10, you *could* get up to a 1GHz Slot 1 chip in there. However, finding one at a reasonable price is the kicker---if it's supported. You might upgrade the RAM if possible too, but I really wouldn't plunk too much down on that system at this point. If you're looking for more grunt, I'd hold onto my money until you could piece together a new mobo/CPU/RAM combo. That'll render alot more power for the money.
Overclocking is making the CPU run faster than it's specified. You've got a 500MHz Pentium III, and overclocking it would have it run any speed faster than 500MHz. How far you'd go depends on luck, cooling, and the CPU itself.
Like I said, you may be able to upgrade it, but I wouldn't consider it a smart choice. I wouldn't pitch it (there's lotsa uses for a machine like that), but if you're looking for extra power, you're much better off building or buying a new box. Hell, you can get a $300 eMachines that'll be a better investment than trying to upgrade that PIII 500 system.
