S and I wrote a children's book a year or so ago and only recently finished making needed revisions and self-publishing it on Lulu.com. We ordered a few copies to make sure it looked good in print and they showed up today and they're fantastic!
The book was created using Open Source tools Gimp and Scribus. The book is released under a Creative Commons license (by-nc-sa 2.0). We decided not to collect royalties, so the price of the book is solely Lulu's publishing costs.
The book isn't perfect--there are some color issues I'm puzzled about. It's our first book, though, and we're really excited--this is a wonderful moment for both of us.