Welcome to Kindlegraph! Through this site, I can now sign and otherwise personalize Kindle versions of my books. This is so awesome! (Hopefully, Nook and other e-readers will follow the same path and soon). You can find all of my books here. I believe you need a Twitter account to participate – which is free and easy to set up.
Please encourage Nook and Sony to hurry up and make these feature available for their e-readers!