Check out the wikipedia site from Rome.
From it you can access untold information.
http://en.wikipedia.org/wiki/Rome
Here is a Google Map of Rome for you to play with:
Roma via Satellitum
Prepare for a trip with Lonely Planet online
http://www.lonelyplanet.com/maps/europe/italy/rome/
Look at wiki's site for the Palatine Hill for a layout of the city in the early Republic
http://en.wikipedia.org/wiki/Palatine_Hill
