Abit's new ST6-RAID board supposedly supports the Tualatin-based P3. They're calling it a "universal" motherboard, for some reason, probably because it supports the current Celeron and P3 chips as well. I've got one now, but haven't installed it... it's based on the 815EP chipset, which I happen to like (as it's not VIA and still supports SDRAM), and it probably is pretty good. I'm no overclocker, but Abit's got a reputation for being overclocker-friendly, and this board is no exception from what I've seen in the manual. 6 PCI slots and IDE RAID support... very nice.
Of course, I don't have a Tualatin processor, just a 1Ghz FCPGA P3, heh...