We've got the new Harry Potter and the Prisoner of Azkaban trailer recently seen on BBC's Film 2004 with Jonathan Ross. Thanks very much to Richard for sending it in! Enjoy.
Windows Media format (2.7MB, ~1 minute) - powered by Streamload
Windows Media format mirror (copy) on MuggleNet
QuickTime format (1.8MB) (courtesy DanRadcliffe.com)
Real Media format (916KB) (courtesy DanRadcliffe.com)
MP3 audio only (1.16MB) (courtesy Potter World Online)
DanRadcliffe.com has also created some screencaps. Thanks Jenna!
Dave from Wizard News points out that this could be an extended version of the 30-second Super Bowl spot, which means it's technically a teaser, not a full-blown trailer. Trailers generally include more dialogue and use actual music from the film's score, which John Williams is still working on.