It looks like, a lot of people have legacy application using Struts and want to integrate them in a Portal. It is not surprising since Struts (fathered by Craig McClanahan, who is also the father of JSF) born in 2000 was so popular and was solving most of the problems of web development at that time.

It also seems that lot of developers think they invested enough time learning Struts that they want to use it forever, so they start developing new applications using it.

For both cases, JBoss Portal supports Struts through the Apache Struts Bridge, yesterday i added on (the currently messy) portletswap.com a new application which is the current demo application of the Struts bridge pre-configured for JBoss Portal 2.6.2. (Note that it will not work out of the box on any earlier version)

The demo application is the famous jPetStore running as a portlet. The application is available here. Just grab the war file and stick it to your deploy directory of JBoss AS, and a new page will appear with the portlet on it.

Note that if you are using JBoss AS 4.2.x or JBoss EAP 4.2 you will need to start it by passing an extra parameter:
-Dorg.apache.catalina.STRICT_SERVLET_COMPLIANCE=false
It can be done by editing JBOSS_HOME/bin/run.conf and adding it to JAVA_OPTS.

This parameter will not be required in JBoss Portal 2.6.3 due in December.

Hope this helps.