I assume that it has a core 2 duo t2300 in it. If so, it is a socket pbga 478. Most, if not all core 2 duo CPU's are of the same socket, but you'll also have to find a chip that runs on 31 watts. If you find something that requires more watts, it will not work, as the motherboard and power supply are not designed to work with such chips. Also, keep in mind that replacing a CPU in a laptop isn't as easy as it is in comparison to a desktop, so be prepared for a battle.
Your best bet would be to save up and buy a new laptop if you are hurting for performance.