The Cassini-Huygens was launched some time in 1997. Some time around last xmas, the Cassini spacecraft releassed the Huygens probe on a direct impact course for titan. Today, it finally got there.
That link leads to more information as to how the probe was supposed to go down to the surface.
After firing off Huygens, the Cassini probe made a deflection maneuver to prevent from plunging into Saturns largest moon as well. For the rest of its operational life, it will orbit saturn and learn as much as it can.
It was on the science channel a few days ago, but I've known about that for a while. They're going to have to figure out a way to get it there, with the ability to drill through the ice, live underwater, take pictures, take calculations, and not contaminate the water before they can do it. I think they estimated that it would be done in 2011 or something.