One more important point on biking in Rome:

YES, you can get to the Fumiciano airport, with your bike, on a train. HOWEVER, it's a moot point, cuz' you're going to want to box your bike before your get to the airport - there are NO bike boxes (that I could find) at the Fumiciano Airport in Rome.

After some on-the ground research in Rome I learned that there is a regional train that leaves from the Tiburtina Metro stop in Rome for the airport, which allows bicycles. Great! The Lonely Planet "Biking Italy" book that just came out has some vague wording about major airlines often having boxes available for bikes. I called United Airlines the day before I left and they said if they did not have a box that I could get one from Lufthansa. Well, I can tell you that nobody at the airport has bike boxes. Everyone I asked just shook their head and said that's something the American companies do. I even hopped a shuttlebus (with my loaded bike) to a different terminal to ask about boxes there, no go. Instead of a box they give you a large, heavy duty plastic bag. After desperately seeking a bike box for over an hour I had to give up and use the plastic bag. I removed the pedals, dropped the seat, bled the air from the tires and turned the handlebars. Luckily I had a roll of 3" wide heavy duty packing tape, which helped secure things, but I still felt like I was giving a lamb to the wolves when I checked it in. Amazingly, my bike survived with no major casualties! (And I had 4 connections, including a customs inspection). However, I can't recommend the experience. If you're flying out of Rome the only option I see is to secure a bike box, pack your bike the day before, and bite the bullet and pay the exorbitant taxi fare to the airport. Not sure how much it costs, but it's a 45 mile trip so it's bound to be pricey.