There is another article up on DeveloperWorks about DWR, this time getting DWR to work with portlets. From the article:
The article uses DWR to build a sample Ajax application based on three portlets with the Jetspeed 2.0 portal.
"With DWR, it's almost as if JavaBeans were available in the browser. DWR simplifies your work by hiding almost all the details of Ajax and allows you to concentrate on the task at hand instead of the nuts and bolts of Ajax development."
It's worth a read if you are thinking of using DWR in a portlet environment.