I was running a slot 1 PIII 650 oc/d to 975 but it decided to die so I'm now running a celeron 366@456 :P measely I know but I'm buying parts for a new comp. Anyway I bought a aluminum WB from
http://www.leufkentechnologies.com/watercooling.shtml but their webpage has since moved. BeCooling makes a clamp
http://becooling.safeshopper.com/6/13.htm?710 . Basicly all that you would have to do is buy a waterblock that has the inlets on the side and you could build yourself a hold down very easly with an old computer case (for scrap metal) and a Dremel tool.