Here's the # from the "Important numbers" thread.
Rapid Rover Shuttle Transport Service (to/from Philadelphia Airport or Philadelphia AMTRAK Station)
(856) 428-1500
From past experience, you do not need to make reservations when flying in to the airport. Just go to baggage claim area and there is a transportation counter and they will set you up on a van to the hotels. Returning to the airport, you do need to make reservations in advance. I believe they like 48 hours notice. Depending on what time you are leaving you can set it up to be picked up at the hotel or diner.