Recording Pens

I want a pen that can record what I am writing on an index card or slip of paper, and upload it to my PIM.

Because my cellphone / PDA doesn't always have a charge.

But I would prefer not to have to use that big acoustic sensor. Want a freestanding pen.

Of course, I would prefer not to have to carry a special pen.  I could scan after the fact  But if a special pen kept charged long enough, it would save a step.