Eman is correct here. Silicon, I think you're thinking of the mobile P2, which went up to 366 w/a 66MHz bus, IIRC. However, there was no P2 366 made for the desktop.
EDIT: Wait, I think you're thinking of the *Celeron* 366, which did indeed jump up to a 100MHz bus pretty easily.
Also, alluu: A P2 333 almost guaranteed won't do a 100 MHz bus; at least, I've never heard of a successful such OC. And, chances are the mobo is an LX, so it won't do a 100MHz bus anyways (83MHz is likely the highest). You may want to recommend that your friend get a Celeron instead. Anyone know if an LX mobo could handle a Celeron2 with a slocket?
-brennan