Yeah, I think it was Iceman reabsorbing the ice. In the last issue of X-men, the end, Sage freezes her hand on Iceman by touching him, then he unfreezes it by reabsorbing the ice, so I'm pretty sure he can either reaborb it into himself, or disperse it among the air.
If we're talking about 616 Iceman:
a. he can melt, but the fact that he emmanates extreme cold makes it difficult. if melting him would be as easy as melting normal ice, he wouldn't be able to exist a good majority of the year. presumably, around extreme heat (check Iceman of the Icons mini), he can still exist, as well as neutralize the heat with his cold blasts.
b. at times, it's seemed as if they are inexhaustable. after all, he did create a new body out of another person's life-water. that's pretty nuts. it depends on who is writing him, if he is in one of his powerful moves, and upon the prescense of moisture.
c. i believe reading that his ice is stronger and harder than normal ice. in all practicality, it would be as strong as any ice we've ever seen, as there are rarely chunks of ice as large and dense as iceman or his slides anywhere besides the poles.
d. he can transform it by simply unfreezing and freezing molecules. thus, the form isn't really moving, because its not the same molecules moving, but it looks like it is. he made a little statue-fight show for kurt once.
e. he doesn't just control ice, he controls temperature, so yes. it's really just a matter of what he chooses to freeze or thaw.
Ultimate Iceman has showed extreme signs of power, such as the Ultimate War Ice-wave (which I believe has been one of the biggest shows of power in the Ultimate Universe, which I'm gonna make a thread about), and flash-freezing an entire Sentinel.
Of course, at other times he can't even Ice-up. So his power level varies. He has definitely started stronger than 616 though.