The Eclipse Wiki is a pretty cool source of information. If you’re curious about the Eclipse Rich Client Platform (RCP), there’s a section in the Wiki that discusses it and organizes a collection of links, references, books, etc… everything you need to know about RCP. It’s your basic one-stop-shopping source of information on RCP.
There’s lots of other information on the Wiki. While your there, be sure to look around and see what some of the other projects are doing…