I love the movement in this and, well, the composition in general! I also must confess my absolute glee at the fact that you took the time to pay attention to their clothes rather than just coloring them on (big fan of stories, but hater of cheap art jobs that result because of spandex).
The drawing (and coloring!) is really awesome. One small criticism: I don't think Superman's hands are large enough to make the foreshortening believable. They're almost the size they would be if they were at the same distance as his face. But otherwisewicked.