Jim Brotherton created this very useful document that describes the modules, features and business tasks that user perform in Enterprise Portal http://www.microsoft.com/downloads/details.aspx?FamilyID=0a0abfc4-964f-43ee-ad26-3d5d4c156269&displaylang=en. We have produced lots of good documentation for EP in AX 2009 and continue to look for ways to adding even more. If you have suggestions, please post a comment to this blog post with the topic name.