There is one example in the EOD repository of a Spring with Ajax. It just uses DWR (Direct web remoting) to handle all the Ajax. This is actually a nice way to handle the ajax. This way you can just expose a few of your spring bean classes to remote calls (only those you markup in the spring config file) and then using one line of javascript you can call into your spring bean class. A pretty hassle free way to integrate ajax technology and spring. See more here:
http://directwebremoting.org/dwr/server/spring