FYI: Sunday, 4/4/10 the shuttle service did not pick us up from our hotel to go to the airport & we almost missed our plane. This was despite a confirmation E-mail back from them. We haven't heard back from them yet w/an explanation why they stood us up.
For once Steve is absolutely correct, for others use the front desk to arrange the shuttle. Most likely the hotel is collecting a small fee from the shuttle company so they will make sure it shows up. Also, our experience is you pay the hotel and the hotel gives you a slip for the driver so there are no surprise charges when you get to the airport.
We waited from 4:17a-4:55a for the shuttle & then ran over to Termini Station where we were able to get a taxi--for 17 Euro extra, but at least we made it to FCO in time for our plane.
We did try to book via our hotel prior to booking directly w/the company. However, due to translation problems, we almost lost our hotel reservations & then never understood that we wanted shuttle reservations.
"For once Steve is absolutely correct"........please note the date and time for future reference.