Yep. The BMW TV module has a analog and digital TV tuner inside allowing you to pick up over the air TV in your BMW. The TV tuner antennas are either mounted in the rear bumper or the rear window depending on the model.
This isn't something thats exclusive to the M3, its being available across the model range, and was first introduced in the 7er, back in 1999. The digital tuner was introduced around 2004/5 ish ... if memory serves.
For safety reason, depending on territory, once the car goes over 3mph and/or the handbrake is released the picture blanks out, although the TV sound can still be heard.