First, thanks so much for the howto!  It saved me a great deal of time.

I wanted to add a post about a problem that I had that took a while to figure out.  After adding webmin, I couldn't navigate to the http://user:10000 page.  It forced me to go to an https://user10000 page and login.  Unfortunately, you can only login as the root user, and for whatever reason, it didn't copy the root password that I assigned when I installed ubuntu intially.  After much gnashing of teeth trying every combination of root, root@user, 'root', etc.,  I decided to try changing the password for webmin.

http://www.webmin.com/faq.html Step 2. Has the instructions for doing this from the command line.

Worked like a champ after that.