I remember seeing and hearing a lot about this project when I first started getting into the NYC scene. It’s a 2005 documentary shot by Daniel Leeb of Cinecycle about bicycle messengers in NYC. There’s more information at the Vimeo page, so check it out.
Edit: Daniel Leeb had the trailer pulled because the owner of the Vimeo account didn’t have permission to upload it. Cinecycle has been working on a new version of this video, so expect that to drop soon!