There's absolutely no difference between accessing an EJB from a portlet as there is from a
Servlet. Just do the JNDI lookup, get the home, obtain the remote interface, call the methods and catch the exceptions.
Absolutely no difference at all.
Here's a tutorial on invoking EJBs from a Servlet. No difference with a portlet:
How to write EJB clients with WebSphere and Rational Application Developer [ November 30, 2007: Message edited by: Cameron McKenzie ]