The Vault (more or less) via Archive.org

Some sharp Deadheads realized that the Official Grateful Dead Trading Policy does not prohibit Archive.org (a noncommercial site) from hosting GD recordings for public downloading. So recently the site managers started the process of transferring the "best" versions of available recordings to their servers, year by year. As of this writing, 1244 recordings are there, with new ones added daily. They won't have every show that's in The Vault (over which the Gratefuls are still negotiating with Apple for iTunes availability), but it will be close enough for most collectors. (Plus, the shows on Archive.org are in "lossless" CD quality, in addition to compressed MP3 versions.)