Hi bryantms,
First things first, are you starting from an installation of the Desktop Edition of Ubuntu 8.04, or the Server Edition? Use the Server Edition if you are setting up an Ubuntu server.
The release can be downloaded from
here, and then burned to CD/DVD. Just click on the download link. And BTW, on October 30 Canonical will be shipping 8.10 which should then be available for download at that download link.
-- Tom