Migrating a whole running Java EE environment from one Java EE server implementation to another is like moving from one IDE to another.  All IDEs do pretty much the same thing.  All IDEs UI are similar yet different enough to be bothersome until you develop a sufficient familiarity. A majority of their underlying functionality is also the same yet each has its own nuances.  To help you make the transition from other Java EE server implementations to the current JBoss EAP or community releases, Red Hat JBoss provides a micro web-site, Migration Center. The web-site provides the following,

• Migration planning and preparation advise 
• Guides for becoming familiar with JBoss' server UI and features 
• Vendor specific migration assistance, for example there is advise for replacing Oracle WebLogic's CommonJ Framework and the Work Manager API. 
• Tools that simplify the migration of applications and server configuration settings.
  • Windup, a Java application that simplifies Java application migrations
  • WindRide, a JBoss server configuration migration tool
  • Tubame, a set of Eclipse plugins that assists in migrating Java EE applications
• Access to the JBoss open source community for discussions, assistance, and topic contributions
  • Migration fourm
  • Migration IRC channel
  • Migration project repositories
• Access to Red Hat Consulting Services, the JBoss migration professionals