It could be changed to another Socket P processor (Core 2 Duo T5xxx or T7xxx) with a 35W TDP. Make sure the latest BIOS is installed.
Although honestly, Core 2 Duo's are so slow by today's standards that I don't think it's worth it, especially with 2 GB of RAM in the thing. You can pick up a modern Pentium or i3 laptop for a couple hundred that would blow any upgrades you could do to this laptop out of the water. I have an old T5500 that I can't even stand to use.