The Kindle has a built in cell receiver so that you can wirelessly browse, preview and purchase books using one-click.
There are converters available from Amazon and/or Mobi for pdf and doc files.
Non-DRM Mobi books, like free e-books found online in Mobi format, or files you convert to Mobi files, are already supported on Kindle.
A cheap casioppeia allows me to read ebooks around 2001.
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.