Forum Romanum
Outlines of Roman History: Institutions of Early Rome: The Early Roman Religion
Early Roman religion was based on the family with a strong "head of the family" in Jupiter. Because the early Romans were an agricultural society, much of the religion also centered on nature.
Franco Cavazzi
Roman Empire: Roman Religion
This site describes the Roman religion. It explains the gods and goddesses and their origins, prayer and sacrifice, offices of the state religion, festivals, and the beginning of Christianity.