for current oc, you want an Asus CUSL2 mobo, they support the 133fsb fully, so you won't damage your agp or pci bus.
As for cpu.. hmm. depends, if you're lookin for value, I think 566 cellmine is your best beat, but be warn, most of them can do 850 easily, but almost none.. I mean.. NONE will do 1ghz+, if you're aimming for that, try to find some old CBO intel PIII 700e, I think they're currently the only chip that is capable of oc to 1+ ghz using convential cooling. By old I mean week 24 or so, don't get anything pass that, intel started to sort the really good 700e then and label them 933.. hehe..
Otherwise, 566 is your best beat, almost all will go to 850, but even w/ my chip.. which is a very very good chip, since it can do 901 at 1.7v, I still have trouble getting it to 950, even at 1.8+v