You must have the board revision 1.00 (check the silkscreen on the motherboard), which is probably a good chance you have that
. Get the latest bios and you should be ok if you do have the P2B-F model and not another P2B model. I believe the max spec PIII cpu is 1GHz at 100FSB. They make it in slot 1 or PPGA (requires a slocket adapter) so get whichever. Do make sure you have indicated the right P2B model. The original P2B is a little different story.
***Hey I run Intel... but let's get real***