Okay, this map is absolutely fascinating. It doesn’t work with 100% smoothness, but my very limited knowledge of one or two parts of Rome tells me that it’s accurate. You click and drag the little girl (sounds harsh, but there it is) in the direction in which you want to go. The map even shows inner courtyards and such. It’s not as if you can print it out and take it with you or anything, but it’s sort of fun.
Update: Zadok’s right. It works better if you use the cursor buttons, not the mouse, to move the little girl.