For more information about the laws applying to government surveillance or other requests for personal information, you might be interested in the following:
The Electronic Communications Privacy Act, 18 U.S.C. ? 2701, et seq.
http://www4.law.cornell.edu/uscode/18/pIch121.html
The ACLU's web page about the USA PATRIOT Act
http://www.aclu.org/SafeandFree/SafeandFree.cfm?ID=12126&c=207
The Center for Democracy and Technology's web page about government surveillance
http://www.cdt.org/wiretap/
The Subpoena Defense Alliance
http://www.subpoenadefense.org/
For information on accessing the contents of a deceased person's mail, click here.
If you have specific concerns about requests for your personal information, you may want to contact one of the organizations listed above or your own attorney.