English speaking private guide for Rome

I will be traveling to Rome for 3 days in late October and early November 2012 and I am looking into the possibility of a private guide in and around the city of Rome for myself and two friends to make the most of the short time we will have to spend there. Does anyone have any recommendations they can share with me based on your recent past experience? The guide would need to be fluent in English and also need to provide transportation for the three of us. Approximate cost and e-mail contact information would be appreciated Thank You, John