Macports is a great tool to easily install a ton of open source software on your Mac. The packages are generally very well maintained but that can be a little tough for very complex ones like The Gimp, the best (?) open source image processing software out there. Though you can download a prebuilt version of The Gimp, I wanted to build my own in order to leverage some third party plugins, like Tilt Shift photography.
If you haven't yet, install Macports.
Then kick things off with "sudo port install gimp". This will likely generate a very impressive list of dependencies and start chugging through them. Expect this to take hours, not minutes. Hopefully, it will build cleanly all the way through. If not, the following notes may be of use...
My first failure (bug #26084) was quickly resolved thanks to the lightning support of the Macports maintainers (kudos to ryandesign [at] macports.org). Turns out I was a building a slightly out of date package. Following the advice to "sudo port selfupdate" and "sudo port clean libgnomeui", the build proceeded smoothly.
The next build failure was already captured by bug #25962. There are three errors listed, though I only saw the first two. These were easily addressed with a couple of "ln -s" commands as described in the bug. I also installed select_python ("port install python_select") and pointed it to python2.6 as described in the comments.
The final bug occurred when building gimp itself. You can check out #26095 and its simple fix.