Counter-Spy Products.

[-V-]

http://www.advanced-intelligence.com/counter.html?2371

Holy crap. I want that cell phone jammer, how awesome would that be in a heavily crowded business street?

 

[Hellblazer]

You can build a cell phone jammer for around ~$50, if you can find the parts.

Nice link, I like the GPS Jammer personally

 

[Nomad]

I like the idea, but this gives criminals privacy to plot things that could be stopped by police tapping their phones.