We've known for some time already that Amazon's AZW files are actually Mobi files, but Amazon didn't share Kindle's Mobi PID which would allow one to buy encrypted Mobi books for Kindle.
Typically ebook readers are larger than PMP's with larger screens. If you're going to read for a few hours, then the screen of a typical PMP becomes pretty eye-straining (due to size, contrast, and brightness).
A cheap casioppeia allows me to read ebooks around 2001.
Devices like the Sony Reader, Cybook, and Kindle DO NOT have glowing LCD screens.
A revolutionary portable reader that wirelessly downloads books, newspapers, magazines and blogs to a crisp, high-resolution electronic paper display that looks and reads like real paper, even in bright sunlight.