I saw this mentioned in a old thread from 2006 and I think it's worth mentioning again. It's a brilliant idea and I plan to order one. I believe the inventor of this is a member here.
It has all the information first responders need and is easy to see and locate (red tag on your jacket zipper), which is perhaps the most important part. I can tell you from experience that the laminated "in case of emergency" card that you might have in your jacket pocket, pants pocket, wallet, or tank bag is absolutely useless in an accident. Fortunately I was conscious to tell the paramedics what they needed to know.