1. Here’s one from ThinkGeek
2. This one is cooler-looking though, I think. And let’s face it: if you’re going to get into this kind of technology, you owe it to yourself to try and feel as cool and “spy” as possible. (More devices from that retailer)
3. This noise generator is cool too, if crazy expensive: “The ANG-2200 is designed to create a perimeter of noise around a target area that defeats wired microphones inside walls, contact microphones, audio transmitters located in AC outlets, and laser/microwave reflections from windows.”

{See also: Spy Museum, countermeasures, Tyco SpyTech toys from when I was a kid (which I can’t find a web page about, oddly!)}