Amazon Kindle's Blog: Kindle Personal Documents Permalink
For anyone who has recently sent personal documents to your Kindle, we'd like to let you know about some updates to our Personal Document Service (via Whispernet).
Starting May 4, in addition to the existing list of supported file types (DOC, HTML, JPEG, GIF, PNG, BMP, TXT, AZW, MOBI, PRC), you can send RTF files to your Kindle email address for convenient wireless delivery. In addition to the existing experimental support of PDF, you can also send DOCX files for conversion. Some complex PDF and DOCX files might not format correctly on your Kindle.
We have also modified the fee associated with sending personal documents wirelessly to your Kindle. This fee is now based on the size of your file. The fee for Personal Document Service (via Whispernet) is 15 cents per megabyte rounded up to the next whole megabyte.
If you would like to download your personal documents for free, or if you are not in a wireless area, you can continue to send attachments to 'email@example.com to be converted. These documents will be e-mailed to your computer at the e-mail address associated with your Amazon.com account login.
As always, you can also use our free document conversion service for any document you want to transfer over USB, and you will not be charged.