Parody is a work created to mock, comment on, or poke fun at an original work, its subject, or author,

     or some other target, by means of humorous, satiric or ironic imitation.

while...

Satire is a strong vein of irony or sarcasm, but parody, burlesque, exaggeration, juxtaposition, comparison,

     analogy, and double entendre are all frequently used in satirical speech and writing.

Reference: http://en.wikipedia.org/wiki/Parody; http://en.wikipedia.org/wiki/Satire