Get a free copy of Ubuntu Desktop Edition and Ubuntu Server Edition. Ubuntu is available free of charge and you can get the latest version (8.04 LTS (Hardy Heron)) with no extra cost, but the delivery may take up to ten weeks, so you should consider downloading the CD image if you have a fast Internet connection.
If interested you can request your copy here
Note : You have to register to their website before making any request. Click here to register yourself.