Untrackerd lets iPhone users wipe historical location data from their devices, but only on phones that have been jailbroken to run unapproved apps.

Want to wipe location-tracking data that's being stored on your iPhone without your permission There's an app for that, but you've got to jailbreak your iPhone first.

Several tools have cropped up as a fix for people riled up about the fact that iPhones (and iPads) are surreptitiously logging unencrypted location-related data on the device, including cell tower coordinates, time stamps, cell operator and Wi-Fi networks used, and longitude and latitude from GPS signals--basically a when-and-where of your phone's location going back at least a year.

Police have known about and been using this information, and cellular operators have access to it and can provide it when served with a court order. But anyone with physical access to the phone (and access to a desktop backup of the data) is now able to see an iPhone owner's whereabouts over time.

The fact that consumers don't realize that their phones are recording and storing this information in clear text has come as a big surprise to many people, including consumer advocates who say it's a big privacy violation.

You can hide the data that may be on your desktop by encrypting your iTunes backups. And you can turn off GPS to stop the logging of at least that information, but that doesn't clean up any data stored on the device, and it will severely limit use of the device for location-based services like mapping. There is no way to disable the tracking, because it's baked into the operating system.

The only option at this point is to use one of the programs written specifically to delete the data. But, as unapproved iPhone apps that reach into the iOS functions, they're not available through Apple's official App Store. They're unsanctioned apps that run only on iPhones that have been jailbroken--devices in which the operating system has been unlocked so owners can run any application they want.

Canadian programmer Ryan Petrich released a tool Wednesday called Untrackerd, which deletes the location-tracking information from the device. The app runs on iOS 4.0 and higher and installs a so-called "daemon" program that runs in the background, continuously cleaning up the data in the "consolidated.db" file where it is stored. "No new icons are added to your homescreen," according to the description on TheBigBoss.org. "There are no options to configure."

Untrackerd, which also is available from the Cydia third-party app store, deletes any data more than 30 minutes old from the consolidated.db file, checking every 5 minutes (except when the phone is in sleep mode) for changes to the file. The most recent data is left intact so the device can still pinpoint the phone's location for driving directions, for example, Petrich told CNET today.

The app does not zero out the deleted data multiple times, as is necessary to prevent bit-level analysis during forensics from unearthing data written to permanent storage. Meanwhile, whatever Untrackerd deletes on the device gets mirrored when the desktop sync is performed, he said.

"I did not make any attempt to make sure it is completely wiped from the disk or [to] wipe any other private data," said Petrich, an Edmonton-based software programmer for mobile ad company Medialets. "I try to maintain the functionality of consolidated.db...[which is used] to improve the performance of location services."

Asked why he wrote the tool, Petrich said: "I created it because I wasn't 100 percent comfortable with the entire history of my location being stored on a device that is very easy to lose."

Another tool, Location Blocker, goes further and wipes all historical data from the consolidated.db file and also blocks the device from storing any further cell and Wi-Fi location data. Step-by-step instructions for installing it are here.

Petrich said he didn't know of any other tools that would help iPhone users get rid of this data. He also said he didn't know why Apple was logging the data but said he doubts it is for malicious purposes because "it's not being transported anywhere."

Update 5:27 p.m. PT: After talking to CNET, Petrich updated Untrackerd this afternoon so that it will securely delete the data it wipes, writing over the disk space with zeros several times so deleted data cannot be forensically uncovered later.