The Directory provides information about former and current senators.
The Senators page on Statistics & Lists is a great resource for information about current and former Senators. Statistics are available on a variety of topics, including biographical characteristics and Senate service records.
This list of Senators' suite and phone numbers in pdf format is updated every couple of weeks at the beginning of a new Congress.
This chart shows the relationships among Senate leaders and officers who manage the flow of legislative and administrative business in the Senate.