WideStudio is an Integrated Development Environment (IDE) for building window applications in C++, Ruby, Python an Perl for Windows, MacOSX, Linux, FreeBSD, SOLARIS and other unix and BTRON and T-Engine. This is open and free (under MIT/X Consortiun Lice
Support for any platform other than windows seems minimal. I have, sort of, gotten it to build under Fedora 18. The GUI has numerable issues -- menu spacing is off, for instance, and the product of the build is unusable. There are no RPMs or deb files (or anything other than the wndows zip file) newer than 2005. Using the source out of the box requires numerable changes for updated libraries and APIs.
Very useful project!