Since printers don't print white the iron on transfers don't transfer the white color from your image. So if you are printing on colored fabric you will want to iron the iPod screen onto white fabric. To do this:
Cut out the iPod screen on the printed sheet
Lay the screen on the white stretchy fabric and outline it with a pencil
Cut out the rectangle you just traced. It should be the same size as the iPod screen
Attach the white rectangle to the dress using Steam-a-Seam. Make sure its centered and you've left enough room for the iPod wheel.
Place the iPod screen graphic over the white fabric on the dress and iron it on using the directions from the iron on transfer package.
Place the iPod wheel under the screen. Make sure its centered. Iron the wheel onto the dress using the directions from the iron on transfer package