It may not be the Nike + iPod, but the Brando USB Pedometer is quite a bit cheaper and can still keep track of all of those steps. This device can record walking data for up to three days. Then simply plug the device into a Windows PC (sorry Mac users, no dice) and get all of your walking data, including calories burned and more.
The USB pedometer can clip on anywhere, but watch out, it looks like a target and could be interpreted wrong if you happen to be in Iraq, or a shooting range. This cheap pedometer can even take over your entire life with its integrated calendar and alarm. The Brando USB Pedometer will be available in November for $17.