Over 3 years ago I wrote a plugin for the Xplane Flight Simulator.
This uses a SDK that Ben Supnik and myself created 6 years ago.
Our plugins are DLL's that our plugin manager DLL loads at run time.

The plugin embeds python and allows python scripts to be run from within
Xplane.
This has worked fine with python 2.3.x, 2.4.x, 2.5.x and 2.6.0.
I see the same problem as described here when using 2.6.1 with the
ctypes, socket libraries etc.
This also affects PyOpenGL as it uses ctypes.

I applied the patch that Mark posted and rebuilt python26.dll.
I tested this on Windows XP and Windows 7 Beta.
With the patched python26.dll my scripts now load properly.
The script that uses PyOpenGL also works fine now.

I thought that this feedback may be useful.