Go out and pick up Ric Steve’s book on Italy. My wife and I would have died without it. It’s easily the best guidebook to Italy and I’ve heard the rest of his European guidebooks are just as good.
A couple of things I learned from our trip and you may want to take note of these, especially if it’s a honeymoon trip.
1. If you’re looking to spend time with people while over there, do not rush around and see as much as you can. Italy requires several visits to get the full flavor. We visited 6 cities in 10 days. that was stupid. We spent a lot of time traveling rather than enjoying. You may want to go for two weeks and spend one week traveling and another week in a villa outside of Siena doing nothing but enjoying the sun, eating, and sitting out at the pool.
2. Figure out which museums you want to go to before you get there. There are WAY too many to try it all at once. I recommend the Borghese and the Vatican.
3. You can find really stylish clothes there for cheap. If I could do it again, I would’ve half-packed all of the suitcases and shopped like a demon. The problem was we were traveling by plane, train, and bus, so that brings me to my fourth point.
4. You might want to think about renting a car. The only place you don’t want to drive is Rome. A car will give you the freedom of getting to places when you want to get there and not have to sit in train stations at 5:30 in the morning.
Good luck on your trip.