Here’s a good article on design patterns for RIA.
“Rich Internet applications (RIAs) can provide opportunities to design much better user experiences. They can be faster, more engaging and much more usable. However, this improvement is not without its downside—RIAs are much more difficult to design than the previous generation of page-based applications. The richer interaction requires a better understanding of users and of human-computer interaction (HCI). Although there is a lot of HCI material and research available, it can be difficult to determine how it applies to this new environment.”