US Federal law enforcement officers have been seeking to have cellular phone companies provide, without a warrant or probable cause, information on subscribers. The information requested includes the caller's location and the particulars about calls made. This week, a US Federal Court Judge in New York has denied the US Justice Department access to this information without a warrant. According to eWeek, this decision is similar to one made by a district court in Texas last month.
From eWeek: NY Court Bans Feds from Tracking Cell Phones.