The SharePoint team has finally released a tool that's been floating around inside the MSFT walls for quite some time.
SPDisposeCheck is much like FxCop - it is a post-compile examiner. SPDisposeCheck will help determine whether or not you are properly disposing of your SharePoint objects. It's worth noting that the tool is designed to highligh potential problems with disposal, you will be required to evaluate the reports and make design choices.
If you're a developer, this is a must have for your toolbox.