If you want to you can... Here's a list of processors to choose from
http://shopper.cnet.com/4566-3086_9-0.html?filter=500119_19753589_
Make sure that your BIOS allows it and the rest will be fine.
People here have done it and it has worked.....
Things to keep in mind:
Socket,TDP, BIOS and RAM Support, plus sometimes the Chipset.
Also make a note of the heat given out and the cooling solution used.