[via Paul Andrew]
Today Microsoft released a tool on MSDN Code Gallery called SPDisposeCheck. It will look at your code in a SharePoint to make sure you are properly disposing objects to ensure you aren't consuming more memory than you need to be. This tool is incredibly helpful as this one one issue that many customers run into unknowingly. IMHO, all your projects should be run though SPDisposeCheck before deployment.
Microsoft is also updating the dispose best practices article in the SDK that will walk you through how to use this tool as well as updated info along disposing of SharePoint objects.
Run, don't walk, and download this tool today!