Epubor
I downloaded the software, and while it was very easy to use, it did seem like a very powerful bit of software. It easily converted my part of kindle books to plain text, so I am very confident that it will allow me to convert the full books to other formats. I would have given it 5 stars, but the trial version does not allow for conversion to other formats, so I can not be 100% sure that it will in fact do this....but I am very optimistic.