Following the controversy over the iOS App "Path" uploading user Contact data to their servers without permission, Apple has responded through a statement to AllThingsD indicating they will address the issue much in the same way they protect user location data:

“Apps that collect or transmit a user’s contact data without their prior permission are in violation of our guidelines,” Apple spokesman Tom Neumayr told AllThingsD. “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.”

We're not sure if this will be included in the upcoming iOS 5.1 release expected to launch with the announcement of the iPad 3 or if it will come later.