via Bruce Schneier...
Old -- but recently released -- document discussing the bugging of the Russian embassy in 1940. The document also mentions bugging the embassies of France, Germany, Italy, and Japan.
Also...
A long list of declassified NSA documents. These items are not online; they're at the National Archives and Records Administration in College Park, MD. You can either ask for copies by mail under FOIA (at a 75 cents per page) or come in person. There, you can read and scan them for free, or photocopy them for about 20 cents a page.