My wife and I road around Italy for a month in '05, mostly in the South. If you do fly into Rome, there is a good campground in Ostia, a very short bike ride away. We stayed there, then just kept riding south along the coast, leaving Rome proper for later on. Also, I think that you can easily get into the city by train from Ostia. We did later on do some riding around Rome, but it was an adventure. Also, there is a campground on the western side of the city that is pretty nice and we managed to ride from there to the Airport pretty easily to head home.
The TCI maps others have mentioned are great. I was surprised, though, that they are not real easy to find on the go over there. There is another brand of map was much more common and definitely inferior. So, I would suggest getting at least some maps beforehand. A couple of US stores sell them online.
Camping was more expensive than expected and often for not much more, we could get a tent or cabin. So, maybe just leave the tent at home.