The Ancient Roman World Start here.  This site has absolutely everything you will need including primary source documents.  (I borrowed this background and line from the page.)

Ancient Civilizations This site is a generic site pertaining to various ancient civilizations Rome being just one.

Ancient Civilizations Tons and tons of links pertaining to many ancient civilizations including Rome.  WOW!

Ancient World Web Another site with oodles of information pertaining to the ancient world.

Roman Coins Information on the history of the coins, the markings the metals form which they were made and more.

Ancient Coins Frequently asked questions about Roman and Greek coins are answered.