I originally found the process module via ROX Desktop, in ROX-Lib2's processes Python module.
I made some changes to it to suit my needs, such as removing a dependency on GTK and using threads to monitor process output instead.
You can read my latest posts about this module, and Python in general, here:
http://goldenspud.com/blog/python/
You can download the latest releases of process here:
http://goldenspud.com/process/releases/
As this work is derived from ROX-Lib2, this software is licensed under the GNU LGPL license.