How it works:

The LaceLid^TM is a firm rubber holder for your Nike+ iPod sensor that you can attach to the laces of any shoe.  Get a bundle of LaceLids and leave them on all of your shoes.  Then simply pop the Nike+ sensor out of one LaceLid^TM and into another! 

Will the sensor work on a shoe other than a Nike?

Yes, the sensor will work on the laces of any shoe.

Is the sensor as accurate on the laces as under the foot?

Yes, the sensor is just as accurate on top of the shoe for running and fitness walking speeds.  For slow walks, the sensor may not be as sensitive on the laces and may miss some steps.

Is the sensor secure in the LaceLid?

The sensor is completely captured by the LaceLid when your shoes are tied.  When loose, the pod relies on friction to hold it in the LaceLid, so it isn't quite as secure, but it does allow for quick transfer from one shoe to another.

The advantage this setup has is better wireless transmission since the signal is less shielded by the foot.

Can the sensor get wet and muddy in the LaceLid?

Yes, the sensor is open to the elements, but this really isn't any different than if it was tucked inside your Nike+ shoes which have a non-sealed hatch for the sensor.  The plastic housing around the sensor is sonically welded shut so it is waterproof.  If the sensor gets muddy, just wipe it clean or hose off your whole shoe just like you would if you weren't wearing it.