As the above post states, all you have to do is get a larger size 2.5" SATA harddrive. Installation is a breeze and you should be able to do this easily by removing the battery. There is documentation on apple's website on how to do this. It should be under support and user installable parts. Hard drives are going pretty cheap. If you don't have a lot on the harddrive you can do a fresh install. If you don't want to lose a bunch of information you can use a free utility like carbon copy to clone to the hardrive to the new one, but you will need an external hard drive case that fits 2.5" drives.
