Check this site out:
https://shipit.ubuntu.com/
This is a service created by the Ubuntu community to give out free copies of the latest Ubuntu version (including free shipping); great for those of us that don't have broadband. Also, if you want to play around with another distribution, here's another site that send cds of Fedora Linux for free:
http://www.pogolinux.com/systems/linuxcd.html
Hope it helps...