I attended the NJ Infragard meeting last week. One of the speakers was a guy who runs a company called Murray Associates. That non-descript name hides what they really do - they are a group that will do an internal security audit for things like wiretaps, microphones, and other such devices. The demonstration was very impressive. Some of the equipment they had were able to pick up any electronic devices. It was kind of amazing to see what they could do in counter-spying.
Murray Associatesweb site
The speaker has an interesting blog up on his Web site, detailing some security topics and spy things that show up in the news, I've bookmarked him!
Kevin Murray's Blog