The March 2010 issue of Scientific American has a fascinating article on the latest scientific knowledge about Titan. Unfortunately, they only have a
preview on their website, but this issue is well worth grabbing for anyone running games in the Deep Beyond. It has details on the moon's methane cycle, which has shaped the surface of the world in very similar ways to Earth's water cycle. It has the latest maps. It speculates that there might be periodic mega-methane eruptions on the world which smooth out the surface. And there are even hints that there might be an underground ocean of liquid water somewhere in there!