Although not a personal guide, we recently used Dark Rome Tours. The Coloseum tour was very good and it had about 20 people on the tour. You have an individual ear phone to hear the guide. The best tour we booked through them was their "semi-private" Vatican tour. The tour cost 89 euro per person. It is limited to 8 people, but there were only 6 on our tour. The guide was an young American woman with a degree in art history. She has lived and studied in Italy for over 5 years. We walked right into the Vatican Museum at 8:10 a.m.
It was a great tour.

The same question was asked yesterday:



http://www.fodors.com/community/europe/recommendation-for-tour-guide-in-rome.cfm


From my 2007 Rome report:


The next morning at 9am, we joined Sandi and her husband, Michael for a private tour of the Palatine Hill and Forum with licensed guide Francesca Caruso.

chris.fra@mclink.it

This proved to be one of the highlights of our week.

We had made several previous forays to the Forum, during which we wandered about clutching a guidebook, trying to make sense of what lay before us and, at times, straining to hear the commentary of other English-speaking guides.

This time, our experience was completely different. Francesca presented the Forum in context and, without spitting out a lot of dry facts and dates, she wove a spell of what life was like during the period.

I was sorry whe the tour ended, about 1pm. We paid half of the total cost, about 70 Euro, and it was well worth the price. Francesca is the leader of many of Rick Steves' tours in Rome and is highly qualified and personable. Her English is impeccable.

More on the guide I used in Rome, Francesca Caruso:


http://www.ricksteves.com/news/tournews/guides/francesca_08.htm

We used Francesca Romana del Fattore fr.delfattore@gmail.com several years ago for the Forum, and she is also licensed for the Vatican. A lovely person with a great depth of knowledge. Email her directly if you are interested.

I can also recommend Francesca Caruso. I've had her as a guide on two separate visits to Rome and she does make a tour very enjoyable.

Her new email address is:

Francescainroma@gmail.com

The Rome Tourist Board has lists of licensed guides, but I'm not sure they keep it up to date as I think they still have Francesca's old e-mail listed. The list does include the languages the guides speak and phone numbers.

http://en.turismoroma.it/vivi_roma/guide_turistiche

http://www.provincia.rm.it/siti_esterni/turismo/elenco1.htm

We (family of 4, kids at the the time 9 & 11) also used Francesca Caruso for our trip to Rome two years ago. She was fantastic and truly the highlight of our three weeks in Italy and France.

After our initial contact, she gave me a general idea of a tour of the ancient sites; I asked if we could also see the Basilica San Clemente, which she thought was a great addition. She helped us get our Roma passes and even bought some snacks for the kids to take with us since I had expresed some concern that we may need to get them something to eat along the way.

After the 4+ hour tour, we paid her including a healthy tip as we had gone over the alloted time, plus just thought she was so wonderful. We then said our good-byes and wandered around to find something to eat. Half an hour later she caught up with us - said we had overpaid her! We couldn't believe that she had spent that time trying to find us because she thought we had paid too much!!!

You wil not be disappointed if you book her.