My friend and I will be in Rome in Sept. and will be purchasing the Roma Pass. Most websites that I have seen say that with the Roma Pass you can skip the long lines at certain places, like the Colosseum. When I arrive there do I just present my pass and that allows me to skip the lines or do I have to do something ahead of time in order to avoid the lines?
I haven't actually used the pass, but have been researching it for this fall. If I understand correctly, the pass allows you to skip the lines to purchase tickets (since your pass serves as your ticket) Since the ticket lines are the longest, (due to making change, running credit cards, etc) this is where you save time. Generally, once you have a ticket you just show it to the person at the gate and you are in.
Connie is correct. For the Colosseum, the long line is the line to buy tickets. Holding a Roma Pass is the same as having a ticket in your hand already. Instead of getting in the ticket line, you head straight for the security line and go through the metal detector. I assume they check your pass either before or after the security checkpoint.
For the Borghese Gallery, you have to make a reservation in advance. Then, you show the Roma Pass at the ticket counter and essentially get a 'free' (i.e., prepaid) ticket. You have to pay the reservation fee in advance if you reserve online, however I heard a rumor you could no longer pay a reservation fee and not purchase the full ticket. Maybe someone else can confirm/correct me on this.
If you are going to use the pass somewhere else (Capitoline Museum), again, you just show it at the entrance and walk right in. The Roma Pass is the same as having already bought a ticket for whichever site you are visiting, allowing you to bypass the line for purchasing tickets, but not for security.