As Steel knows, my wife has the same thing and absolutely loves it. She joined a web challenge for most miles by a beginner through the month of January and it has been very motivational for her. Of course, the leader in her challenge already has 130+ miles logged for the month - hardly a beginner by any stretch of the imagination.
She opted for a sensor and arm pouch by Marware:
http://www.marware.com/cgi-bin/WebOb...Lj0vT8wsvCFOBg
The arm pouch seems a bit more functional than the apple version due to the fact that you can see the display while in the pouch and also that it can be used as a wrist strap. The shoe sensor is probably not quite as good as Steels, but it works well enough and came pretty cheap as a bundle package through Amazon, $24 for both:
http://www.amazon.com/MARWARE-Armban...UTF8&s=apparel