If you want to record music, the four track is out. Now, you need to record on your computer, digitally. But to do that, you need a way to plug your guitar into your computer. There are a bunch of connectors that let you plug your guitar into a USB port, but they're expensive. Why not just build a guitar/mic port right into the front of your computer?
Over at Instructables, they have step-by-step instructions on doing just that, which should make your home recording sessions a bit easier. It'll take a little elbow grease (and a soldering iron), but hey, nobody said being a musician would be easy.