This week's book giveaway is in the Performance forum. We're giving away four copies of The Java Performance Companion and have Charlie Hunt, Monica Beckwith, Poonam Parhar, & Bengt Rutisson on-line! See this thread for details.
Whenever anyone asks me anything about integrating AJAX with a Struts project, I generally tell them to use the DWR framework. It integrates nicely with a Struts project and it takes a lot of the work out of using AJAX.
Check out this thread for a further discussion of Struts and AJAX.