Transportation in Rome
Many monuments are within short distances between themselves, which go from one to another, it is best done on foot. However, it is a big city, and there are distances that are convenient not to make them walk.
As much as Rome has subway (very small … with only 2 lines), the best way of moving from one place to another, in our view, is to use the buses. The bus system, in addition to night services, and many lines that cover the entire city, has the great advantage of being “FREE”!
We’re not going to recommend not to pay the ticket, but hey, we in the 4 days we were, we took several buses to go to many places of the city, and none of them pay the ticket, nor an inspector climbed. If an inspector to climb, you can always play bell and get off at the next stop! 
For those wishing to pay your ticket (as it should be …), you can buy them in the “Little shrines (kiosks where they sell magazines) and the” tabacaios “(cigar). Sometimes they are sold in bars. Drivers do not sell.
The cost of the ticket is 1 € (at least it was in September 2007), like the subway, but with the difference that you have paid the departure and return, if you use the return trip in 75 minutes.
How to go Rome from Termini?
As mentioned above, Termini is a good starting point. We give you a list of bus lines have to take to the musts:
64 Colosseum Online
Piazza Venezia and the Vatican line 64
Plaza of Spain and Trevi Fountain line 492
Campo di Fiori line 64