Gmail's setup guide is pretty good too: http://goo.gl/IIMgg

And yet yesterday I had someone call me up after I provisioned them with a Google Apps account and the link above (Google Apps's Settings screen links to the IMAP version of it). They thought they had to set up a Gmail account first because all the screenshots show 'username@gmail.com' instead of 'username@myappsdomain.com'. The screens were also alien to them because they showed a different OS version.

This is definitely fixable. I like the idea.