Ted Husted has put together an impressive training course together for Struts 2 called Apache Struts 2 from Square One. He's released an initial version of the 127-page PDF on SourceForge.
Thanks Ted! The fact that you're contributing this hard work to the community (for free!) is amazing.
I'm teaching a 3-day training course in May that covers Spring, Hibernate, Maven 2, Ajax and AppFuse. I'm not sure if the client wants Struts 2 or Spring MVC for their web framework. If they want Struts 2, you can be sure I'll checkout Ted's course as a starting point.