"OC Team Italy" over at the XtremeSystems forums have been working towards breaking the 8GHz barrier with a Pentium 4 631 processor, and with some modifications to their cooling methods along with voltage mods, they've finally done it!
Nordic Hardware have more details here folks.
We reported a while back about how OC Team Italy had unpacked it golden Pentium 4 631 to throw some liquid nitrogen on it. With a non-modified ASUS P5B motherboard they managed to reach a whopping 7520MHz, but pointed out that the motherboard made it impossible to go any further. Now that they have once again mounted the copper pipe and made the necessary voltage modifications, the liquid nitrogen once again did its thing and made it possible for them to finally reach 8000MHz! We bow and congratulate them for this historical achievement and we're eager to see if this will remain the record or if more will bring out their Pentium 4s.