Joe Kissell’s book is hands down the best guide I’ve seen to upgrading to Lion. He takes you through the questions you need to answer before upgrading, downloading the installer and
Perhaps most helpful of all, Kissel even covers Apple’s new built in Recovery mode if you need to re-install Lion.
I used Take Control of Upgrading to Lion before, during, and after my own Lion upgrade; it was exceedingly helpful. The one change I’d suggest is perhaps adding a note about moving or copying the Lion Installer before beginning the install to the Quick Start page.
You can read the table of contents and the introduction to Take Control of Upgrading to Lion.