Apple announced Wednesday that application developers will have to receive permission from iPhone and iPad users before accessing and storing their contact lists. The move comes amid privacy concerns that developers of apps like Path and Facebook were saving users' contact information without consent.

Two U.S. lawmakers—Rep. Henry Waxman, a Democrat from California, and Rep. G.K. Butterfield, a Democrat from North Carolina, sent a letter to Apple CEO Tim Cook last week asking if the public's privacy concerns were unfounded.

"How many iOS apps in the U.S. iTunes Store transmit information from the address book?" they asked. "How many of those ask for the user's consent before transmitting their contacts' information?"

Waxman and Butterfield asked Apple why users could opt out of allowing an app to access location information but could not similarly opt out of having their contacts collected.

The letter was spurred by an iOS app developer named Arun Thampi, who blogged about his discovery that the social networking app Path was accessing and collecting the contents of his iPhone address book. The app never asked permission to harvest this information.

In an E-mail sent today, Apple spokesman Tom Neumayr explained Apple's new policy. "Apps that collect or transmit a user's contact data without their prior permission are in violation of our guidelines," he said.

"We're working to make this even better for our customers, and as we have done with location services, any app wishing to access contact data will require explicit user approval in a future software release," he continued.