The Colosseum as of July 2008 is approx 11 euros entry for an adult. You will queue about half an hour or so and then you can purchase an audio guide for four euros.
Be careful - you will get approached many times by people offering you the chance to queue jump as they have a reservation and they will take you on a 40 minute tour for 20-25 euros. Sounds good, but don't go. Basically there are real tours that go through a different queue. When these tour groups get to a certain part the group leader will pay for everyone at the ticket office and then take you on a tour. However they do not really check whether the tours are official. So what these other people are doing are taking you through to the ticket office using the tour queue which may be ever slightly quicker, and then they are purchasing your tickets and keeping ten euros themselves after giving you a quick unofficial tour. I would advise you queue in the normal line and use the official audio tour guides for four euros.
If you are unsure whether the people you are talking to are real staff at the Colosseum, I can tell you that they all wear a uniform. The uniform we witnessed was black t-shirts and black trousers. So all these others outside in their own clothes are unofficial guides.
The Colosseum can be found easily but I advise going to a newsagent or to the kiosk at Termini Station or another metro station and purchasing a seven-day pass. It is 16 euros and entitles you to seven days on buses, metro and trains, unlimited use. Get off at Colosseo stop for Colosseum or Termini for Trevi fountain, Spagna for spanish steps, etc... or travel for 40 minutes to Loro Central and it's a ten minute walk to a lovely beach! Great value for money! Metro comes every three minutes, absolutely fantastic!
Send your feedback or queries to email@example.com