Check it out:
http://www.info.nike.com/media/pr/2008/04/01_Sportband.html
Released this Thursday. Looks like it's going to retail for £39.99, seems pretty reasonable as it will also be bundled with the Nike+ sensor, which along with the watch will be all you need to get started. It works in the same way as the existing Nike+iPod system, but instead of the run data being sent to your iPod Nano, it get's sent to and displayed on the watch,
Should appeal to those looking for a speed/distance monitor without needing to buy an ipod nano. Or as in my case, will appeal to those already using the ipod nano system, but want an alternative for when taking music with you isn't really ideal, e.g. races where ipods aren't permitted, running with friends, running in wet weather, when you don't want to risk damaging your ipod.
Nike store in London will apparently be stocking them from Thursday this week, and this online retailer will have them in stock on the same day - www.foot-traffic.co.uk. Not sure when they'll appear on the Nike Online store.