Most of us geeky free software advocates forget that just handing out CD/DVD of gnu/Linux is not enough to get people started. It is always a good idea to suggest a book that's available in a local book store that will help learning by exploring. There is a lot of documentation and manuals that are already bundled on installation disk and also installed by default but nothing really compares to the joy of reading a printed book.
The current version of Ubuntu is 8.04 , better known by its code name Hardy Heron. And since things change from one version to another I rather suggest a title that is updated and revised to reflect the changes in latest version. Browsing through the bookstores I found this one from Apress publications called 'Beginning Ubuntu Linux' by Keir Thomas and Jaime Sicam. This book in third published edition seems to be a fully revised. It covers not only installation and basic customization but also introduces various Linux Multimedia software and Office tools. The book features a nifty reference of Linux terms and of course a DVD copy of Ubuntu and its derivatives like Kubuntu, Xubuntu and Edubuntu.