The GameBoy Pocket edition
The GBA edition
The Tamagotchi edition
..there are also sightings on cell phones, TVs, games, books, pencils, toys, McDonalds, entire stores, Hot Topic, usenet, usb hubs, MaximumPC, laptops, stores, shoes, and various inapropriate places..
The following was picked up in an alt. group... obvious sign of infiltration...
/^\_(>o<) | | | O . O | -Niao! \_______/