Carmunicate’s original Carmunicator used the cassette tape player in vehicles to reproduce the telephone conversation through the vehicle speakers. The new product works with MP3 player systems, or any audio setup with the universal 3.5mm jack socket.
The i-Carmunicator can be moved easily between vehicles. It can be used to turn almost any PC (laptop or desktop) into a speaker phone by plugging it into the microphone socket of the PC. This enables conference calling or simply to allow the user to have both hands free for other activities.
Info from www.carmunicate.com.