The Amazon Kindle e-reader device can download new reading content directly from the online Kindle Store. It also allows you to transfer your existing library of e-books to the device from a computer. Although the Kindle is compatible with a variety of different e-book formats, the Broad Band eBook format -- which uses the LRF file extension -- isn't one of them. By converting your LRF-formatted e-books using a free online tool, you can create a .mobi, or mobile, version that is fully compatible with the Kindle.
Launch your computer's Web browser and navigate to an online e-book conversion tool such as Online-Convert (online-convert.com) or Zamzar (zamzar.com) by typing its URL into the browser's address bar.
Click the "Choose File" button and locate the LRF-formatted e-book you want to convert. Click the "Open" button once you've selected the e-book file on your computer. The e-book will be uploaded to the online conversion tool.
Click the "Convert" button once the e-book file has been uploaded, and wait while the conversion tool processes it. Depending on the size and complexity of the e-book, this can take a few minutes.
Save the converted .mobi e-book file to your computer when prompted by the online conversion tool. The e-book file will have the same name as the original e-book, which you can change by giving it a new name in the "Save" dialogue box. Click the "Save" button to save the converted Kindle-compatible e-book to your computer.
The .mobi e-book can be sent to the Kindle by connecting the device to your computer via USB cable and copying the e-book file into the Kindle's "documents" folder. Zamzar users can enter Kindle's unique e-mail address to have the e-book sent directly to the device after conversion.