This will be the "first mission to the last planet," as their webpage puts it, although now they'll probably have to change that statement. They plan to launch the spacecraft in January 2006, and if all goes according to plan, it'll encounter Pluto in July 2015 and then continue on to study the Kuiper Belt. I've actually been waiting for this mission to launch since the 1990s, and I'm glad it's really happening. The spacecraft will get us some fascinating close-up pictures of Pluto and Charon, of course, but the science payload also includes devices to study Pluto's atmosphere and its interaction with the solar wind. Perhaps New Horizons will reveal just how Pluto and Charon were formed in the first place, and settle the question of Pluto's status as a planet once and for all.
And, by the way, New Horizons will be carrying a CD with the names of anyone who signs up to have their names sent to Pluto. Just click here if you want to be a part of it. You'll get a cool certificate you can print out and hang on your wall to show your support of the mission.