Eclipse is an open source Java IDE, with a built-in CVS client. This client can connect to a CVS repository via :pserver an internal SSH 1.0 client (:extssh) or through any external connection program (:ext) like other SSH clients.
The main idea behind Eclipse is the fact that it's expandable by plug-ins which seamlessly integrate into the the IDE. There are a lot of plug-ins available: Some are free some are even expensive.
IBM's Websphere Application Developer (WSAD) is Eclipse extended with plug-ins for J2EE development, testing and deployment. But Eclipse is still the base and so CVS is a supported version control system for WSAD. The same thing is true for all other Eclipse based IDEs from IBM's Websphere Studio family.
Unfortunately the eclipse CVS integration is poorly supported and is not recommended, even with the latest version 3.x

