Microsoft Advanced Group Policy Management integrates with the GPMC and adds a couple of great features that allow you to better manage your GPOs. By providing a check-in/check-out system for when GPOs are modified, you can track which user modified a GPO and what they did. You can also roll the GPO back to a previous snapshot. Other features such as off-line editing and cross forest management are also included.
Jeremy has a downloadable chapter at www.GPanswers.com/book and its part of his Advanced One Day training.