A little while ago, Amazon came out with Kindle for PC. A bit later, someone out there had a script written so that you can read most Kindle books with Mobipocket Reader! They can also then be converted to most any other format, but since I have Mobipocket Reader on my Dell Axim X30, there was no need for me to change formats.
I am absolutely THRILLED!!! I often receive Amazon.com gift cards as gifts or as points rewards. Now I can actually purchase Kindle books and read them on the ereader of my choice. Although the Kindle is very nice, I prefer a much smaller unit like the Dell Axim that I can easily fit in my purse. Heck, I'll probably end up spending more than just the gift cards now....
You can find the info on how to do this HERE.
There are some exceptions... if the Kindle book is in "topaz" format, then it cannot be converted. Before purchasing a Kindle book, simply download the free preview first. If you can convert the preview, then you will be able to convert the full book. If the sample will not convert - then neither will the full book. You can still, however, read it on your PC if you don't mind doing that.