http://www.vatican.va/roman_curia/in...040112_en.html
I might have missed the above link in the first posting. It for setting up the tour of the Scavi beneath St. Peter's. Most fascinating tour for me.

http://www.ostia-antica.org/
Great place to spend a day and bring a picnic.

http://sights.seindal.dk/sight/901_Hadrians_Villa.html
Hadrian's Villa near Tivoli

http://www.villadestetivoli.info/indexe.htm
Villa d Este in Tivoli