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.
Use Mobipocket software to convert PDFs to that format so you can read them on Kindle.
As glued to the net as we all are, there's vast quantities of content that is not available online.
The Kindle only allows the reading of Amazon DRM-protected content.
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.