Congressional oversight of intelligence is handled primarily by the House and Senate Intelligence committees. Both committees resulted from the congressional investigations of intelligence in 1975-1976 when it was decided that, among other problems, congressional oversight had been lax.
The House Permanent Select Committee on Intelligence was created by House Resolution 658 (95th Congress) in 1977. In the 102nd Congress ( 1991-1992), it had 19 members (12 majority and 7 minority), excluding the House majority and minority leaders, who are ex officio members. There are three subcommittees -- Legislation, Oversight and Evaluation, and Program and Budget Authorization.
The Senate Select Committee on Intelligence was created by Senate Resolution 400 (94th Congress) in 1976. In the 102nd Congress, the committee had 15 members (8 majority and 7 minority), excluding the ex officio majority and minority leaders. Unlike the House committee, the Senate committee is considered bipartisan -- that is, its composition does not reflect the actual party division in the Senate. It currently has no subcommittees.