In Seam in Action, Dan Allen stated
Seam isn't just about JSF and EJB 3, though. You can swap in alternative view technologies such as Wicket, Tapestry, GWT and Flex in place of JSF.
How difficult is it to swap in these alternative view technologies? Is there some tips or best practices to consider when doing this? Other than the learning curve, any disadvantages to using Flex over Faceletes/Richfaces?
what's the best place to start learning how to integrate Flex with Seam apps?
And does it violate EAP support contracts if we start using Wicket or Flex, for example, with our Seam apps?
Wow, sorry for the late reply I just found this post while doing a search.
In my opinion the best place to start is at www.graniteds.org. There you can find a bunch of applications that show examples and documentation. All though our documentation is still in the process of being improved.
Once you know flex, the learning curve should be pretty small because you can use your back end Seam code just as you would normally. In other words there doesn't have to be anything special in regards to Flex.