the Spy Phone

Sure, you've heard about it. You've read about it. Well, here it is — software that turns any phone into a Spy Phone. You'll never feel quite so secure about that phone in your pocket again...

from Spy-Phone.com:

Product Description

SpyPhone	Spy Phone allows the user to call the target phone (with the installed software) which will result in the phone answering in ghost mode, i.e. answers at zero ring, without lights, call notifications and log creation. No visual or physical changes can be noticed on the target phone. more...
Call Interceptor	Call Interceptor allows the user to call the target phone (with the installed software) which will result in the phone answering in ghost mode (if no calls are active on the target phone), or listen to the conversations of the incoming or outgoing calls (if calls are active on the target phone). The calls will be answered at zero ring, without lights, call notifications and log creation. No visual or physical changes can be noticed on the target phone. more...
SMS Interceptor	SMS Interceptor instantly catches all incoming and outgoing SMS on the target device (where the software is installed) and forwards them silently to the pre-defined number. SMS forwarder has been built via a special in-built SMS Server Engine which assures reliability of the software. more...
Location by SMS	Location by SMS enables the user from the pre-defined number to send an SMS to the target phone (where the software is installed) and get the of the target phone. more...