Yeah, like everyone else, iTunes has fan page on Facebook. If you can stomach the process, you can even get 20 songs for free by becoming a fan. The process is a bit clunky, however, which seems to be par for the course on Facebook. First, you become a fan. Then, you'll need to allow the "Free On iTunes" app to get access to your profile (typical of a Facebook app, of course). Then, you click a link that says "redeem now" -- a link which took me to a blank page.
After digging back into the fan page again, I found that button again, and clicked it again. This time I got the right page, but iTunes never woke up (that is, the store link didn't work). Then I tried yet again to "redeem now" and voila! A page warning that I'd already done all this appeared. Luckily there was a redemption code on this page, and the "redeem now" button finally worked. I am now downloading iTunes 9, iPhone OS 3.1 and 20 songs by indie artists.
If you can suffer the mess that is Facebook, you can get some free tunes.