To introduce Mozart to a preschooler, here is a quick little project: A Mozart Painting.
First step: Tape off a rectangular area on a large piece of paper (the little ones will love to put the tape on)... Have them paint the background, going over the tape to define the borders. Gluing on some old sheet music is also fun.
Step two: Cut out a photo of Mozart (just "google" a photo of "mozart")
Step Three: Glue the picture of Mozart to the paper, we used label paper, so ours came off two halves.
Lastly, pull off the tape and find an old frame to put it in - Your child will love to hang it in their room!