Lite VS Pro Questions:
 

Is there significant differences between the two? How in depth is pro vs lite.

Also, is it hard to upgrade from lite to pro?

just look here
http://www.photoplog.com/demo/index.php

Yes, see the link ragtek posted, and there are also demos available from the PhotoPlog drop down menu in the navbar. The upgrade process from lite to pro is similar to the lite upgrade process.