Digital pens have long been a touch and go technology, which a number of interesting, if stupid, ideas coming down the pike. This one appears to be useful little tool that digitizes handwriting without depending on special paper, touchpads, or ink. It's Bluetooth compatible, as well. However, I just don't know if handwriting will ever take off: consider Tablet PCs. I have never used the handwriting functionality because it's just too flaky. In small form factors, like PDAs, it works well. In the real world, however, it's kind of dumb.
Digital Pen from Hitachi Maxell [101Reviews]