This deal has ended.
Dick's Sporting Goods had the best deal yet on the Nike+ iPod Sport Kit (the Nike+ Sport Armband is a related product). It is $29 but if you spend $1 more (here are some cheap examples) you can get $10 off by using Google Checkout, cutting the price of the Armband to $19, effectively. Also, shipping is now free and there is no sales tax (except CA, GA, KY, MA, PA). This kit turns your iPod and Nike shoes into a very cool personal workout coach, pedometer and performance tracker.