I love GIMP. It took time to learn how to work with it, but it is the best program I've worked with when creating book covers. 
I love GIMP to, I just wish I knew how to use it. I know that I'm only using a fraction of what it's capable of.Sheila_Guthrie said:I'm a big GIMP fan -- all the covers except for the first one, Bound in Amber, were made with GIMP.
I'm using Photoshop now, but when I was just starting out, I didn't want to put a lot of money (any money, actually) into something, and my son told me about the Gimp. Once I got the hang of it, it was pretty easy to use.
I've got some links to tutorials on my blog's resource page, if anyone is interested in learning more about the program. For some reason, I don't have this video linked, though I've watched it, so thanks for reminding me about it!