The St. Louis Fed has recently announced their new Center for Economic Digitization.
http://stlouisfed.org/news/releases/2008/07_03_08a.html."To date, CEDD has digitized more than 300,000 pages of published material and archival collections from the Federal Reserve System and selected partners—currently, the Brookings Institution, the Government Printing Office and the Missouri Historical Society. This storehouse of documents includes U.S. government publications, Federal Reserve publications, photographs, manuscripts, and multimedia formats." All documents are available for public use and are available on the St. Louis Fed's FRASER (Federal Reserve Archival System for Economic Research) website at http://fraser.stlouisfed.org.
Also...the St. Louis Fed has published their May Liber8 newsletter titled "The Economics of War." It is available at http://liber8.stlouisfed.org/newsletter/. This provides a good overview of the issues and difficulties involved in determining the costs of war, including opportunity costs. The article provides a list of resources for further research. While geared for librarians these brief newletter articles always provide a good for an overview of a topic and are useful to researchers and students as well.