How do I use Indexed Properties with Struts 2? (link)
How can I learn Struts 2?
The best place to start with Struts 2 is the Struts 2 Documentation Home Page There is extensive documentation and sample code available on that site. As Struts 2 is very new and has far less market penetration than Struts 1, other resources are fairly scarce.
There is a page in the Struts 2 documentation with pointers to numerous tutorials
Ian Roughley has also written a smaller book, Starting Struts 2 that is available as a free PDF or a dead-tree book. At about 100 pages, it is more an introduction than an in-depth study of the Struts 2 architecture.