GDL is actively developed and has already a lot of functionality. But it is still in beta state as of November 2007. Even though it can already be used for many tasks, there are many things left to be done.
Any contributions are very welcome. Currently contributions can be made in C/C++, GDL and python. See the files HACKING and PYHTON.txt in the GDL root directory.

Urgent things to do are:

• Library functions and procedures
• Porting GDL to other platforms
• Implementing GUI library functions
• Completing the graphical output system
• Testing and test routines written in GDL

You might send your contributions using the trackers or via email. Please put GDL into the subject line.