TorrentFreak published a review of Allpeers. Allpeers is a Firefox extension designed to share pictures, music and video within Firefox. There is also an interview of Matthew Gertner from Allpeers. Actually the sofware is a Beta but look promissing. In the current version, as reported, you can only share files with people in your buddy list (friends and family). But in the future the extension will include a full featured Bittorrent client. You might register here to be notified of the public release. In the meantime, you may download the Beta here.