If you launch any of the studio-version videos in a browser window, Pandora will continuously play the rest of the available videos in alphabetical sequence. It's not quite as full-featured as the main music service (yet, at least), but it's an interesting new direction for the heretofore audio-only service.
Artists, bands and labels with music videos to submit can find out the submission details in the FAQ. You must have created or own the rights to the video you're submitting which, if chosen, will be available for streaming but not download. Some of the 24 launch artists include The Prodigy, Animal Collective and Kid606.
There was talk as far back as two years ago that Pandora would be adding music video to the site, but at the time the rumour was about licensing content from players like MTV and major labels. This strategy is a very different one -- in a sense, Pandora is disintermediating some of the traditional machinery of the music industry and going direct to the artist to ask for distribution.
From the talent list of the launch videos it seems that a sector of established artists are quite happy to go this route. This marks yet another interesting turn of events in the long transition to a digital music ecosystem, which has had its share of very rocky moments as traditional relationships are disrupted.