cpGUI is an easy to use, object oriented GUI toolkit based on SFML 1.5. It's released under the zlib/libpng license.
I've put up a detailed wiki page in the English Projects section that can be found
here. You can download the files from the wiki page, and also see a screenshot.
The wiki has a description of all of the classes and the user functions in each class.
Hopefully someone can get some use out of it.