The Eclipse editor and the Pydev plugin (open source) provides a very powerful IDE for Python.  The Autocompletion functionality is extremely useful.  My goal was to access the Maya Python API through the same autocompletion.  However, the .pyc API files from the Maya release do not provide the python introspection attributes required for this. 

These stub files are generated from the actual Maya docs and enable full Autocompletion and documentation for the Maya Python API in the Eclipse editor.

New since Sept. 2011, the files have been modified to use the "Predefined" option in Eclipse/Pydev.  This is a much easier setup rather than having to deal with the order of module imports (like the older method).

For usage, see the tutorial here on CreativeCrash

http://www.creativecrash.com/maya/tutorials/using-tools-scripts/c/using-eclipse-as-a-maya-ide