[UPDATE: 7:25 p.m.] Android devices have been found to cache location data in a similar manner.

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Freaked out that your iPhone may be tracking your every move? So are Senator Al Franken and Representative Ed Markey, who have called on Steve Jobs to explain the situation.

Researchers found that iPhones and iPads track and record users' locations by latitude and longitude, sometimes hundreds of times a day, for up to a year, storing the file in an unencrypted format on the device.

"Anyone who gains access to this single file could likely determine the location of a user's home, the businesses he frequents, the doctors he visits, the schools his children attend, and the trips he has taken-over the past months or even a year," Franken wrote in his letter to Steve Jobs.

Franken highlights some of the potential dangers of this system, noting someone in possession of a stolen iPhone or iPad could "easily download and map out a customer's precise movements for months at a time." The senator also points out that there's no indication the software can tell the difference between minors and adults meaning that "the millions of children and teenagers who use iPhone or iPad devices also risk having their location collected and compromised."

Franken is joined by Representative Ed Markey in calling for clarity. Both want to know why Apple is collecting this information, how it is collected, what it is used for and who it's been shown to. They also want to know why consumers haven't been told their devices are recording their movements, and why the information has not been encrypted.

Franken asks, "Does Apple believe that this conduct is permissible under the terms of its privacy policy?"

While Franken has asked for a "prompt" response, Markey was more direct: He would like answers within 15 business days.