I just picked up my Jawbone UP from the Post Office last night, so thought I'd post my first impressions.

Firstly, the wristband is pretty awesome. Mine is black and is made out of a rubbery plastic that feels really comfortable. The wristband itself is supposed to be water resistant so you can wear it in the shower. At one end of the wristband is a metal cap which, when removed, reveals a mini-jack plug for plugging the band into your iPhone. The other end is a button, that switches the band into measuring different types of activities - exercise, walking and sleeping.

To get your activity data with your iPhone, you need to plug it into the audio socket of the phone and press the button to sync. So far this hasn't been too onerous, but I can imagine it being a little bit of a pain eventually. The iPhone app allows you to track your time spent exercising, your movements and sleep patterns. You can get it to vibrate if you have been inactive for too long, or to wake you up in the morning.

Overall, I'm really excited about this technology. It's had a bit of a negative review here, but I think the Jawbone UP is going to be great to play with!