If you have an Apple iPod nano (any generation) or an iPod touch (2nd generation only) and you enjoy running, power-walking, or even just long walks, Apple and Nike have partnered to create the Nike + iPod Sport Kit ($29 list), which consists of a shoe-mountable sensor and a receiver for your iPod nano.
The sensor mounts in special Nike + running shoes, but there are instructions in the comments of the link below on how to use the sensor with any running shoe. The receiver plugs into the bottom of your iPod nano or touch. The two communicate and feedback is shown on your iPod screen. Feedback includes your pace and distance run.
When you sync your iPod, the information from your runs in uploaded to a Nike website where you can get even more information about your training.
Shopping online? You can help support Basics4Mac by making your Amazon purchases through this website. Any purchases you make at Amazon by going through this site will give me a small commission. It does not affect the price of the items you buy. Click the link below to get started.