My favorite is the Belkin light . I usually clip it to the side, which works well for landscape or portrait mode reading.
http://www.amazon.com/Belkin-Clip-Re.../dp/B003HKRVAW
I have no idea where my camera is, but I captured a frame from my FlipVideo to show you what it looks like attached to the PRS-950.
edit. Hmmmm. Evidently Flicker is smarter than me this morning, because I can't get the photo link to show the photo. I uploaded the same pic to Amazon, and it's showing in the customer photos for the item. Sorry about driving traffic to AMZN.
http://www.amazon.com/gp/customer-me...newSort&page=0