The Toshiba TW/720LL laptop came stock with a Dothan Celeron M 1.4GHz CPU (SL8ML). I wanted to upgrade it to a faster Pentium M class CPU so I get the SpeedStep feature along with a minor boost in computation speed. Both the Pentium and Celeron are from the same Dothan architecture; so in theory, the upgrade is a simple switcheroo.
The chipset in the laptop is an ATI Radeon Xpress 200M. I had a difficult time looking for the specs to determine compatible processors. In the end, after looking at other brands with the same chipset with different CPU combination, I was certain chipset would work with both 400FSB and 533FSB CPUs.
I purchased a Pentium M 1.89GHz CPU (SL7S9) for $10 on eBay. A 2GHz+ processor would be ideal but that one was the least expensive.
The TW/720LL chassis is the same one as the Satellite M50/M55 laptop. Following the dissassembly guide, I replaced the CPU. Once complete, the laptop was able to boot and displayed the Pentium M logo instead of Celeron. =)