A Nike-Free Nike + iPod Kit

The partnership between Nike and Apple for the Nike + iPod Sport Kit is designed in such a way that you have to buy Nike shoes to get the sensor.
The website podophile.com shows how to adapt the sensor to non-Nike-branded running shoes.

A bit of Velcro, a bit of sewing, and it is done, you get iPod-compatible shoes.
Let's see if Apple will modify the iPod firmware to ensure that you are using the receiver with a sensor located in Nike shoes. ;)