A great source of e-book conversion utilities can be found at http://wiki.mobileread.com/wiki/E-book_conversion. There you will find various commercial, opensource and freeware programs that can handle file formats like LRF, CHM, LIT, HTML, PDF, RTF, PDB and DOC and convert them to formats that the Kindle can handle.
I’ve used the opensource Calibre EBook Management Software and can recommend it without hesitation. It’s available for Windows, Linux & the Apple OS X platforms.
Amazon Kindle File Formats
Note that Amazon offers its conversion via email service for the following file formats;
- Word DOC
- PDF (experimental, results vary)
Software like earlier mentioned Calibre can handle additional formats, such as;