He modded an Asus Eee PC 901 by creating an extra LED to the top left of the device. He used an AtMel AtTiny45 microprocessor, a 5mm red/green/blue LED that would light a different colour depending on which service the message was from. Judging by the ‘how-to’ post, it’s clearly quite a complicated but ingenious mod, which includes programming the chip. Luckily, he got it all to work first time. For the full details head over to his blog post here.
SOURCE netbookchoice.com