The premise is two New Zealanders trying to make it in music in New York City, and features Rhys Darby as their hapless manager, Murray Hewitt (much like the brilliant Stephen Merchant as the similarly hapless Darren Lamb in Extras), Kristen Schaal as the obsessive number one fan Mel, and the members of the real life comedy duo Flight of the Conchords, Bret McKenzie and Jemaine Clement as themselves. Also look for the short appearances of the similarly hilarious Judah Friedlander and Eugene Mirman. The tone feels in some ways like a mixture of the UK version of The Office, Rushmore, and Christopher Guest films, with a healthy mixture of Bret and Jemaine breaking into songs such as this one.
When taken in sum, it is an excellent pilot for a series that I will be sure to keep an eye on as it progresses. Also, I really liked the description of Jemaine Clement as "an ogre who works in a library" in the cast and crew section of the HBO website. Flight of the Conchords premiers tonight after Entourage on HBO, but you can watch the premiere episode for free (Update 10/6/08: Not!).