21 Lutetia is just a pit stop for Rosetta (except that it didn't stop, of course... it whizzed by at over 33,500 miles per hour). The spacecraft is now making its way to rendezvous with the comet 67P/Churyumov-Gerasimenko, where it will arrive in 2014. Rosetta will orbit the comet and drop a landing craft, named Philae, to touch down on the surface. If successful, this will be the first mission to land a craft on a comet.
Below, an image of 21 Lutetia captured on July 10th. Saturn can be seen in the background.
Courtesy of wikipedia:
Churyumov-Gerasimenko has a rather interesting orbital history. Comets are regularly nudged from one orbit to another when they encounter Jupiter or Saturn in close proximity. For this comet it was calculated, that before the year 1840 it was completely unobservable due to its perihelion distance of about 4.0 AU. At this time Jupiter shifted that distance to about 3.0 AU. Later on, in the year 1959, another encounter with Jupiter pushed it to about 1.28 AU, where it is now.