I tried out Dave's OPML editor this morning. Hours before the pending public release. The UI concepts are exactly similar to Radio Userland. Creating an outline and uploading it to the server was trivial. Congrats Dave! I'm still unsure what the application is.
GET IT HERE!!! >> http://support.opml.org/download << GET IT HERE!!!
Update: My OPML Editor blog.
Update: Dave's "brief podcast to celebrate the public ship of the OPML Editor".