Nick and I tested the different ways you can use that sensor to monitor your workouts using your iPod Nano and the Nike Sports Kit. It appears a certain company came up with yet another alternative, a Sportsuit Sensor+ that fits any shoe. Tiny as it may seem, the suit is made of neoprene and rubber, and attaches by slipping the strap underneath your shoelaces, and fastening it with a strong velcro closure. Expect to pay $10 for the sensor suit. Product page