However, its been a while since they updated their application. So, there are no new version released. This means that it will not be compatible with new mac OS X. I myself is on Mac OS X 10.6.3.
I did some research and found some answer on how to install it on Snow Leopard .
Here how it works. Install the app from their website. And when you open it for the first time, it will crash. The reason are the fontconfig and iconv libraries distributed with GIMPshop are not compatible with the current X11 environment.
Ok.. First u have to built universal variant of Macports.
sudo port install libiconv +universal expat +universal freetype +universal zlib +universal fontconfig +universal
Then remove the offending libraries that come with GIMPshop and replace it with the new one. The library can be downloaded from this website.
sudo rm -f /Applications/Gimpshop.app/Contents/Resources/lib/libfontconfig.*
sudo rm -f /Applications/Gimpshop.app/Contents/Resources/lib/libiconv.*
sudo cp libfontconfig.1.dylib libiconv.2.dylib /Applications/Gimpshop.app/Contents/Resources/lib
sudo ln -s /Applications/Gimpshop.app/Contents/Resources/lib/libfontconfig.1.dylib /libraries/libfontconfig.dylib
sudo ln -s /Applications/Gimpshop.app/Contents/Resources/lib/libiconv.2.dylib /libraries/libiconv.dylib
This commands should work with Snow Leopard.