I have a Revision 1.0 of the ASUS P2B 440BX motherboard, just like the poster here. I got a Pentium III "Katmai" 600MHz, using the 100MHz FSB and having 512KB of L2 cache on a Slot 1 cartridge and it works perfectly fine. In fact, it ignores the CPU multiplier jumpers on the motherboard, so you don't even have to bother with that - though you are welcome to move jumpers around if you want to.
My Windows 98 system is living proof that your motherboard will support up to a 600 MHz Katmai Pentium 3 processor. Just make sure you're using the latest BIOS. You can use the Pentium II and a floppy disk to do that.