As the title says, these methods are not available in the US as of yet. But, if you are planning on moving to the UK or Japan, you are in luck.
The most interesting way to attempt to protect your cell phone is Wired's first on it's list: The Screamer.
The Remote XT harasses UK cell-swipers with a loud, high-pitched human scream (the service puts a recording of a woman shrieking on your phone). The system activates when the owner calls a hotline. The nerve-jarring wails accompany a complete data wipe and button lockdown, creating one useless piece of plastic.
So just picture a guy walking around in some library or department store. All of a sudden you hear a loud high-pitched scream coming from the man standing next to you and it appears to be coming from his pants pocket. I would hate to be him as you read the headline of that story in the newspaper of his arrest.
Other methods include GPS tracking, holster recognition and "voice & strut" recognition.
[Read full article at Wired]