Another method is to pour your chilled ice cream mixture into a bowl and stick it in the freezer. During the freezing process, take it out every once in a while and beat it with a hand mixer or whiz it up in a food processor so it doesn't freeze into one solid lump.
If you're adventurous, you could even use liquid nitrogen. How awesome would that be? I'll tell you: too awesome.
If you're going to be making homemade ice cream frequently, though, I do recommend purchasing an ice cream maker. It's easier than the other methods, I think. I've got this one
($50), and I really like it. There are cheaper models, too. You should be able to pick up a basic maker for around $20 - 25.