If you really want a free way to get you books set up for Mobile phones and PCs then try out smashwords.com.
They have a formatting guide to set you through all the steps and then their "meatgrinder" will format everything for you from epubs, pdf's to HTML and JAVA based readers.
You DO NOT have to publish the book to the public when you are done or sell it there, but it is a free source online that does almost all the work for you and makes a really good product once you have formatted your ebook to the style guide specifics.
It's also free and you don't have to download anything!
I have copies of my book in every format from there backed up on my computer and I sell it there too, but you really can't beat the price and what they offer.