The Dec. 1 edition of CQ Weekly (Pitt subscription) has several excellent articles about secrecy in Congress. The cover story is "A Dome Under Lock and Key" which details how much information about Congress is unavailable: "...the secret side of Capitol Hill is not at all limited to military or intelligence policy. For all its apparent openness, its televised debates and public hearings, Congress is more secretive than its reputation suggests. Closed or restricted access to legislative meetings and records may not be the rule, but such behavior is hardly viewed as an exception."
"Sunshine's Irregular Presence at the Capitol" presents a timeline of important dates in attempts to open - and close - Congressional information. "Obama on Openness" reports several steps that the President-elect has promised to take. Finally, "Congress' Tools of Last Resort" discusses ways in which members of Congress can force secret documents to go public.