Since the comments I had on the post about Muffalettas were about not knowing what the sandwich was, I decided I'd better post a link to some information about it.
Wikipedia seems to have some pretty good information on the sandwich all in one place. This entry includes the ingredients and the origins of the sandwich although it doesn't give an actual recipe.
The muffalettas I had in the New Orleans area (I actually lived in Mississippi but the sandwiches were popular there also) were on a thick bread the size of a dinner plate and filled with Italian ham, cheese, & salami as well as the Italian Olive Salad.
The center of the bread was scooped out to make room for the other ingredients and that's why I was taken with the recipe from Rachel Ray. Instead of the thick bread of which much was thrown away, she used pizza crusts. Italian bread and pizza crust are made from the same ingredients in the same way but just take different forms. The taste was the same - crusty on the outside with those toasted sesame seeds - with the rest of the ingredients well-contained so no olive oil dripping on your clothes or bits of olive salad falling on your lap!
If you ever go to New Orleans and you're a meat eater who likes olives, be sure to order a muffaletta! Like the Cafe du Monde's coffee and beignets, the muffaletta is another New Orleans institution!