You'll also want to learn about inserting images directly into your Word document if you're planning to include graphics. As mentioned earlier, images in eBooks can present layout challenges; keeping the pictures relatively small and leaving them centered horizontally on the page is your best strategy.
All three publishers can work with Microsoft Word files, but there are other options that offer more control over the look of your book, and better opportunities to preview the layout before uploading it. You'll find complete instructions about formatting possibilities on each company's website.
You'll also want to create a book cover. You can include a picture or just use type but, either way, the publishers expect you to submit an image file in the standard JPEG format. That means you'll need some image editing software. I like Adobe's Photoshop Elements ($99.99 for PC or Mac), but any program that lets you edit and resize your image will be fine. Another worthwhile resource when building a book cover is iStockphoto.com, which lets you search for images based on keywords, and buy them at reasonable prices. (I paid $15 for the cover image used in a recent eBook.)
Of course, some projects are more elaborate than others. For a straightforward text-heavy eBook, you can probably handle it yourself. If you feel the need for help, and can't find the answer in the publisher's online guides, turn to their user forums, where fellow authors who've gone through the publishing process answer questions and explain some of the finer points. And finally, if it's just too much for you, there's no need to despair. Since the eBook publishing boom, a host of companies has sprung up ready to provide assistance with any phase of the process at consumer-friendly rates – you'll find links to recommended providers at each publisher's website.