From a May 20 Judiciary Committee news advisory: "House Judiciary Committee Chairman F. James Sensenbrenner, Jr. (R-Wis.) and Ranking Member John Conyers, Jr. (D-Mich.) released the answers received last week from the Justice Department regarding the USA PATRIOT Act and the war on terrorism. Chairman Sensenbrenner and Rep. Conyers wrote Attorney General John Ashcroft on April 1, 2003 requesting information on these issues."
Also from the Judiciary Committee, links to the following documents from the May 19 oversight hearing, "Anti-Terrorism Investigations and the Fourth Amendment After September 11: Where and When Can the Government Go to Prevent Terrorist Attacks?"
See also this New York Times article that states the Patriot Act answers include the following information: "federal agents conducted hundreds of bugging and surveillance operations and visited numerous libraries and mosques using new law enforcement tools." From CBSNews.com via AP, "Public libraries have been contacted about 50 times by federal investigators as part of their anti-terrorism efforts, but the Justice Department won't say whether they looked through or took information from their records."