Engadget have released a review of the fitbit networked pedometer. I remember first seeing this about 12 months ago, when it had just launched at techcrunch 50. I like the idea of the device, but it is yet another thing to carry around, and yet another thing to charge.
It makes me thing of the belt valet computers in David Marusek's Counting Heads (Thanks for the reccomendation @doctorow). One day, not too far away, we will have computers that we carry, strapped to our person (perhaps in belt form), that can handle all of the biometric sensing that we want. It will be able to count our steps, work out our heartbeat, and record everything that we hear and see for future reference.
I'm really excited about the prospect, even if it does open up a lot of privacy concerns. It will be important that we as individuals retain control of the information that is being collected. I'm pretty sure that google having access to all of my heartbeat (which is basically an EKG) information would be a bad idea. David's sequel book, Mind over Ship shows us a very good example of the mis-use of complete information on people.