Read The Freedom of Information Act.
Freedom of Information Day is celebrated nationally each year on the anniversary of James Madison's birth, March 16; Madison was the chief author of the Bill of Rights and 4th president of the U.S. The purpose is to focus public attention on the importance of citizenry's right to government information in a democratic society. (Text adapted from Chicago Public Library)
The FOI Act established the right of citizens to obtain information from federal government agencies. To learn much more about your right to request government records, read the information on the National Security Archives FOIA web site (through George Washington Univ. - D.C.). The American Library Association also has more information on Freedom of Information Day.
A First Amendment Center Online research compilation examines the procedure for filing requests for government information under the federal Freedom of Information Act. It provides an introduction to the act, information on the Privacy Act, how to get started on an FOIA filing, what you can and can't obtain through FOIA requests, pitfalls, appeals and more.
The CIA offers an Electronic Reading Room "to provide the public with an overview of access to CIA information, including electronic access to previously released documents. Because of CIA's need to comply with the national security laws of the United States, some documents or parts of documents cannot be released to the public." Sections on the site include How to file a FOIA Request; How to file a Privacy Act Request; Frequently Requested Records (these include documents concerning UFOs: Fact or Fiction?; Bay of Pigs; POW MIA; Guatemala; Human Rights in Latin America; Atomic Spies: Ethel and Julius Rosenberg; Lt. Col. Oleg Penkovsky: Western Spy in Soviet GRU; and Francis Gary Powers: U-2 Spy Pilot Shot Down by the Soviets); Annual Reports to Congress, 1997-2000; Your Rights; and Special Collections. Documents are searchable. The Freedom of Information Act (1966), the Privacy Act of 1974, and Executive Order 12958, signed in 1995 and which "outlined a uniform system for classifying, safeguarding, and declassifying national security information," are all available here as well.
Closely allied to the concept of "Freedom of Information" is the concept of "Freedom to Read," which includes the freedom to gather information from any source, and the ability for all citizens to have equitable access to sources of information. The American Library Association has created a lengthy and clear statement on The Freedom to Read, which is available at its web site. You're free to read it!