Jupiter Jovians...

[Orion1]

Some researchers believe radioactive and tidal heating may form deep reservoirs of liquid water beneath the ice and that life forms may exist there, enduring the extreme pressures and darkness. Oceanographers have found some bacteria living in such conditions in the Earth's black depths.

Reference:
http://www.sltrib.com/2004/feb/02152004/nation_w/139097.asp

[FZ+]

You do mean Jupiter's satellite, Europa, and Saturn's Titan, right? It has long been believed that Europa has a liquid ocean, from the pattern of ridges and crevasses on its surface. We know less about Titan, but...

I think most scientists believe that Europa holds the best chance for life elsewhere in the solar system.

[Nereid]

A deep global water ocean is also likely within Ganymede and possibly Callisto. Titan almost certainly has surface lakes ... but they're not made of water! Huygens and Cassini will tell us much more.

If the majority of life on Earth is bacteria living in rocks, down to ~10km, then there should be similar life in deep rocks on Mars (below 2km, under the permafrost), and also around whatever remnants of hydrothermal vents there are there.

Not as exciting as cute furry animals or bushes with fragrant flowers ...
[:)]