Whats the difference?
Why do I have to pay for the professional.
Howdy,
You can see a list of the major differences here:
http://www.virtualmin.com/compare.html
Two of the more popular features are the reseller accounts that the Pro version has, as well as the Install Scripts, which provide one-click installations of a number of web applications such as WordPress, Drupal, and the like.
-Eric