I just got the Kandle from Amazon.com. It works great with my PRS-650. I hate trying to use booklights with those long bendy necks because they always feel "wobbly" to me. The Kandle has a short neck that aims the light directly down the length of the screen. Here's the white one:
http://www.amazon.com/Kandle-Designe...8820123&sr=8-1
They also have it in black.