There are 57 Democrats in the Senate and 40 Republicans. There are also two independents who caucus with the Democrats. In addition there is one empty seat that was vacated on the death of Sen. Edward Kennedy of Massachusetts. If this seat were filled, there would be a total of 100 Senators--two from each of the 50 states.
In the House of Representatives (Congress's other house), there are 256 Democrats and 178 Republicans, making for a total of 434 Representatives. There is also one vacant seat. The House normally has a total of 435 voting members apportioned among the 50 states on the basis of their populations. Populous states such as California and New York have the most members. And smaller states have fewer members. Every ten years a census is taken and the results are used to reapportion representatives among the states. The House of Representatives also has six members who do not vote. They represent the District of Colombia and other American lands such as Guam and American Samoa which are not states. For example Eleanor Holmes Norton represents the District of Colombia.
For members of both houses broken down by political party, see: http://en.wikipedia.org/wiki/111th_United_States_Congress#Party_summary
For info on the Senate, see: http://en.wikipedia.org/wiki/United_States_Senate
For information on the House of Representatives, see: http://en.wikipedia.org/wiki/United_States_House_of_Representatives
For a listing of the members of the House of Representatives, see: http://www.house.gov/house/MemberWWW_by_State.shtml
For info on one of the non-voting delegates to the House of Representatives, see: http://en.wikipedia.org/wiki/Eleanor_Holmes_Norton
