I use a
Beam N Read Light LED 3 Hands Free Light with my Kindle 3. It's worn around the neck instead of attaching to the eReader or a cover so it doesn't add weight to the device, is able to shine light from the front instead of from off to one side, and will work with all eReaders. Battery life is 120 hours with regular alkalines. Although I may be biased (I'm from the manufacturer), it's worked great for me for reading in bed and during a recent cross country plane flight. It can also be used for dead tree newspapers and books, for knitting, as a power outage light, and other tasks.