Who remembers the Nike+ iPod Pedometer? Went in your shoe under the insole and connected to your iPod via a separate 30-pin dongle. : r/RunningShoeGeeks
Nike+iPod - Wikipedia
Amazon.com : Pedometer for Walking, Waterproof Pedometer Watch, Simple Step Counter for Walking with Steps Calories Distance Time for Women Men Kids Parents : Sports & Outdoors
Replace Battery in Nike+ Sensor : 5 Steps - Instructables