This found this months JPL von Kármán lecture to be very informative. It provides a summary of the conclusions drawn about Europa from thr Voyager and Gallilio missions, as well as some others sources.

Note for Dial-up users You really can't stream this very well, but if you have RealPlayer Beta you can pause it for about 2.5 hours until it finishes downloading - and then play the full lecture, and also save it to your HD if you want. Just be certain that pausing on demand (non-live) interenet clips is checked under playback settings in your preferences.

JPL MultiMedia Archive

11/15/07 - The Hidden Ocean of Europa ( 1:09 hrs )
Jupiter's moon Europa may be a habitable world. Evidence points strongly to a global subsurface ocean beneath an ice shell.
+ RealPlayer(Streaming with caption)
+ RealPlayer(Streaming without caption)

Jack