NIKE + IPOD SENSOR-USA
The iPhone version I have doesn't require the adapter, so all I needed was the sensor for my shoe, only $19 - lucky me. I also don't own or plan to own Nike running shoes, so I DIY-ed a spot inside the tongue for the sensor. Works wonderfully! Your run (and/or walk) history is stored, then downloaded each time you sync. Easy peasy. I am planning to buy a tiny velcro pocket "thingy" so I can easily wear the sensor with different shoes.