Wes explained the InfoStick to me yesterday. It's a Memory Stick-type card, but it's not a storage card -- it's a Bluetooth network card. When you plug it into your supported Memory Stick device, you'll have access to the other Bluetooth devices around you.

Kind of like a Wireless Ethernet PC Card... but Bluetooth, and in a Memory Stick form.

I found this PDF document which describes the InfoStick in a LOT of detail.

Another article that mentions Infostick.

Since I don't have any Memory Stick devices, this is of little value to me now, but at now least I understand what that magic little stick-of-gum sized chip will do!