If you have a MacBook that's running out of space, you might want to consider upgrading your hard drive. (Ours was, what, an 80 GB that filled up with the OS, various apps, and quite a few photos.)
It's simple if you aren't afraid of screwdrivers and avoiding static buildup; I...
0. Was relieved to see that I already had an external backup drive, a LaCie 160 GB.
1. Printed out "How to Upgrade Your MacBook's Hard Drive" from Macinstruct / Tutorama.
2. Poked around online, read reviews, and picked a hard drive. I chose the Western Digital 500 GB Scorpio 2.5" 5400 rpm jobbie from Amazon. It's an OEM component, meaning all you get is a drive in a static bag.
3. Got the right Torx screwdriver and weird flat pulling / pushing tools from some Amazon vendor. (And recalled that I had a tiny Philips screwdriver already.)
4. A few days later they arrived.
5. Pulled back the static-friendly tablecloth on the dining room table, put a piece of paper on the wood, and got to work...
6. Excluding the initial backup, it took 15 minutes to install the drive and about 1 hour to restore it.
Fear not... You too can have, like, 400 GB available on your MacBook!