I did this a couple of years ago using a photo from our trip. I cropped the photo in to an oval and put it on the front of the shirt, then I found some online Disney clip art sites and sized and printed different things to be ironed on.
The shirt had the photo in the middle, "2003" under the pic "Walt Disney World(clipart)" over the top and (the whole reason I decided to chime in on the thread) on the left sleeve right above the hem I printed (using the scraps/unused corners) and ironed on "Disney" (the one with all the characters as the letters) It was a very nice touch.