They can be done at a Walmart, Eckerd, Target, ect. Not sure if they send the camera away or not. We did regular processing and it was ready two days later, but that's because we didn't want to pay extra for 1 hour processing. I think they stay onsite because everyone is using disposables.
We didn't know this, but the kodak cameras that say Advantix are actually special because the prints you get back are huge. We got two of these (non water) for our trip because they looked cool. They're colorful cameras that are smaller than the regular disposable. We developed the pics and it costed alot of money. We also got two water cameras and those had regular 4x6 prints. Don't get a camera that says Advantix on it, unless you want huge prints.