Cornell Law School, Legal Information Institute
Chapter 119 – Wire and Electronic Communications Interception of oral communications.
http://straylight.law.cornell.edu/uscode/html

Federal Bureau of Investigation
http://www.fbi.gov/

Federal Bureau of Investigation / Counterintelligence Home Page
As the lead counterintelligence agency in the United States , the FBI is responsible for identifying and neutralizing ongoing national security threats.
http://www.fbi.gov/hq/ci/cointell.htm

Loyola Education Department
Articles and reports about strategic intelligence
http://www.loyola.edu/dept/politics/intel.html

NCJRS
The National Criminal Justice Reference Service is a federally funded resource offering justice and substance abuse information to support research, policy, and program development worldwide.
http://www.ncjrs.org/

Privacy Rights Clearinghouse
Information on Wiretapping and Eavesdropping on Telephone Conversation
http://www.privacyrights.org/fs/fs9-wrtp.htm

Wikipedia
Wikipedia is a free-content encyclopedia and is an editable contribution from members from around the world.  Excellent content.
http://en.wikipedia.org/wiki/Main_Page