Retina-X Studios, LLC, announced today the immediate availability of Mobile Spy for the Apple iPhone. Using this groundbreaking iPhone spy technology, users can silently monitor incoming and outgoing text messages (SMS) and call information of children or employees - even if activity logs are erased. (more)
Spybusters Tip #387
Keep in mind that this only for 2nd generation iPhones (3G), and it only let's the spy see a log of calls and SMS text messages. There is no eavesdropping on the call itself. Installation requires "jailbreaking" the iPhone first.
The manufacturer's spyware removal instructions.
(Not yet updated to include iPhone, but should be soon.)