Non DRM Mobipocket format is already supported on the Kindle - just drag and drop.
The Kindle has many flaws, but it does allow you to read a few different non-DRM formats.
Granted the PDF converter seems to have some trouble with graphics PDF's, but for books the converter works very well.
Hacker Igor Skochinsky used DRM to load Mobipocket books onto his Kindle. Using a series of scripts, he's able to convert eBook files to Amazon's AZW format and then add the necessary serial number DRM, specialized per an individual's particular Kindle.
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