From The Movie Snob:

Aliens of the Deep (B). This is James Cameron's new IMAX 3-D movie about undersea exploration, and it is pretty good. He skips past all the familiar stuff, the coral reefs and sharks and dolphins and stuff, and takes these little two-person submarines right to the bottom of the ocean. Specifically, he goes to these big fault lines in the earth's crust where sea water has gotten down to the hot molten core of the earth and comes spewing back out of chimney-like structures in superheated jets of chemical-rich "smoke." Around these chimneys, weird (and mostly very small) creatures (shrimps, crabs, octopuses) live without any reliance on solar energy whatsoever. This leads Cameron to hypothesize about alien life on Jupiter's moon Europa, which may have liquid oceans concealed under miles of ice. I thought it was pretty interesting. But I was more excited about the preview for "Sharks," another 3-D IMAX movie that should be coming out soon.