Cassini has detected evidence of liquid water on Enceladus venting from its south pole. There's been speculation of cold geysers or possibly an ice volcano. This suggests that under the moon's surface ice lies liquid water. This is unexpected, Enceladus should be too cold for liquid water, but there's speculation of an ammonia/water mix that wouldn't freeze at such temperatures. There's also cracks in the ice that suggest at tectonic shifting in the ice.
And curiously the hottest spot on Enceladus is its south pole. This is something of a mystery. Poles as you would expect, usually tend to be the coldest places on a body. Eggheads are being scratched as to what's generating this heat. And to top it all off Cassini has also detected organic compounds. That doesn't necessarily add up to life but the possibilites are mindblowing if you're sufficiently geeky. It looks like Titan has some serious competition for the Saturn's Coolest Moon title.
The BBC has a layman friendly version of the story here. A member of the Cassini Imaging team gets his geek on about this on his blog. These high res images you're seeing here are new but the ice volcano theory has been around since last summer.