Nokia Beta Labs
The applications provided by Beta Labs are still in development, but are considered "mature" enough to be released in order to be tested by users worldwide. After a period of time, an application either "graduated", meaning it is released as a final version, or is removed from the site and placed in an archive.
Anyone can submit feedback about applications, which goes to the development team. Comments and ideas can be submitted directly through the Beta Labs page, or via http://blogs.nokia.com/s60blogs/