If Digi-Key don't have anything, then you can make a socket using 2.54mm pitch single in-line socket strips. e.g. Farnell part number
1218868. I've written
a guide on doing this for BGA mounting sockets, but it's a similar idea for leaded sockets.
However, desoldering the existing CPU is a fairly tricky job. The board is at least 6 or 8 layers, if you damage the plating in one hole, which is very easy to do given the fine tolerances of the CPU pins, PCB holes and PCB track widths, then you're stuck with a dead unit. Hot air would be your best bet, but still a bit risky.
Probably not a good idea unless you're well experienced with soldering and you have a good reason for needing to replace the CPU, such as you know the old one is faulty.
