Portable People Meter (PPM) to collect metering information associated with multimedia data played back by a multimedia presentation device such as mobile digital assistant MDA, portable computer, mobile telephone or other. A wireless headset or earpiece is coupled to the multimedia presentation device via Bluetooth®, and the speaker of the headset emits audio based on the multimedia data received from the presentation device. The PPM includes a metering information generator eavesdropping, on the digital wireless interface of the headset, the audio information from the media presentation device to generate audience metering information associated with the audio data. The implementation of the PPM includes microcode executed on a general purpose processor.