Pentium-M's are not electricly compatible, so won't work in a normal P4 board. If you are refering to Pentium 4-m's aka Mobile Pentium 4's then yes, they will work on a desktop P4 motherboard. I am using a Pentium 4 mobile 1.6ghz chip in a desktop board. There are a couple of desktop motherboards out now, that are for pentium-m's like the DFI board that Ronnie linked to, and Aopen has one as well.