Glade is a GUI builder for GTK+ and GNOME. It stores projects in an XML format and can generate C code from this meta-format. Additionally, the meta-format can be converted to other languages via modules. For example, glade-- can generate C++ code.
Information regarding Project Releases and Project Resources. Note that the information here is a quote from Freecode.com page, and the downloads themselves may not be hosted on OSDN.
Quartz build support was added. Disappearing dialogs on ESC were fixed. Widget naming policies were fixed again. The Python plugin build is now stable.