What is the name of the reading app you like to use on your phone? Is it and Android or iPhone? I'm curious to know what other people use to read e-books.
There is an open source program called Calibre that will convert .mobi to epub and other formats. It will probably screw up the formatting, but .mobi has already done that to some extent
I just compared the .mobi file on my Kindle Reader app for iPhone with the book I bought from the kindle store. They don't look the same. The .mobi has apparently stripped away some of what Amazon calls the "Enhanced Typesetting" features.