Making an eBook cover with GIMP is very doable, which is a relief, since it can keep you from having to spend tons of money on Photoshop.
I searched all over the internet for a tutorial on how to do it well in GIMP and there wasn’t much out there. So a buddy of mine (graphic artist) and I worked at it and figured it out. We created a guide, because to really make a professional-looking ebook cover takes quite a few steps. (You want your ebook cover to be pretty polished, not some ugly looking thing that will turn away buyers!)
The detailed instructions for the tutorial are over on the main site: www.makeebookcovers.com.