Info also available at http://williamgs.com/blog/?p=19

Light Linking in Maya may appear at times to be black magic, this tool aims to
demystify it and make fixing problems effortless for any user.
Unfortunately, some lightlinking tools/scripts actually create more problems.
This tool is designed to safely clean scenes anytime, and additionally provide
tools for efficiently light linking. For more info, read the full help docs, or chcek the link above.

This tool provides a graphical user interface, but may also be run just from the command line (including custom options).

Installation:
1 - Extract and Copy the LightLinkTool folder to your scripts directory, or anywhere in Maya's PYTHONPATH.
2 - To run, save the following Python code to a shelf command:

import LightLinkTool
LightLinkTool.loadUI()

If you find any bug or have feature requests, please post them here or comment on the blog link above.