That's Saturn in the foreground, and the crescent Enceladus behind it. The remarkable bit about this shot is the erupting geysers clearly visible at the south pole of Enceladus (at the very bottom of the crescent; click the picture to make it bigger). Wow. These ice geysers are coming from quarter mile deep cracks in the surface of the ice, called the Tiger Stripes. The Cassini probe keeps making passes over this section, and on this last pass, on Feb 23, observed 30 geysers. This was once supposed to be a dead moon, all rock and ice. Now we know it to be alive with geological activity, and likely hiding a great lake of water beneath all that ice (though the jury is out on that).