He's like Toph with more control. I think the whole Magneto name is misleading, because he seems to be able to control any metal, even non-magnetic ones.
Nevermind, found it, turns out, that was ultimate universe. He manipulated the electromagnetic field around the hammer. And "It should be pointed out that Magneto tried the same electromagnetism trick in the regular Marvel Universe and was unable to affect Mjolnir. Apparently Uru metal behaves differently depending where you live." So I wasn't wrong.
Lemme break it down for you. Marvel has multiple alternate universes. In the ultimate universe, Magneto was able to manipulate the electromagnetic field around Mjolnir to lift it and somehow gained access to part of its power, enough to allow him to reverse the magnetic poles of the earth. The mainstream (616) universe (on which all other universes are based) magneto tried the same trick, but it didn't work because 616 Thor's hammer is pure Uru. Since the marvel universe isn't based solely on any specifc storyline, its hard to say if movie Magneto can lift Movie Thor's hammer.
#wonderingthough
*standing ovation*