They have buckets of these things at the local Zellers here in Toronto.
It can capture your drawings to your PC (plus a ton of other stuff) this might be handy when drawing a schematic that you want to share. The FLY Fusion Pentop Computer Review|Gear Diary **broken link removed**
If you don't have a scanner it's pretty handy. Hey for $20 it's an MP3 player too
It'll also remember several hand written pages of your notes. Of course it needs special paper and if you get bored with it you can always disassemble it (tiny camera inside)
I've heard some folks tried, not sure if successful. It's a light blue set of dots. Logitech makes a similar pen but it's much more expensive. The Fly Fusion talks too! **broken link removed**