Researchers figure out how to crack GSM phone security for $1000, Feb 2008.

Two enterprising researchers claim to have figured out a way to eavesdrop on calls made using GSM mobile phones, cracking open its 64-bit A5 encryption. According to David Hulton and Steve Muller, who presented the technique at the Black Hat security conference in Washington this week, GSM calls can now be recorded over long distances and cracked open in half an hour using only $1,000 worth of field-programmable gate array-aided computer equipment and a frequency scanner. 
"The Washington Post"