SPDisposeCheck tool to help developers comply with SharePoint's memory management best practices has been updated on the MSDN Code Gallery.

Please refer to Paul Andrew blog post for more details: SPDisposeCheck v1.3.1 is released. "SPDisposeCheck is a tool to help SharePoint Developers follow memory management best practices when using the SharePoint API with IDisposable objects including SPSite and SPWeb. This tool is not supported by Microsoft and is recommended to be used on Developer workstations and not on production SharePoint Server installations .... "

Download the tool here: SharePoint Dispose Checker Tool

The updated Best Practices guidance document is here: Best Practices: Using Disposable Windows SharePoint Services Objects

I would highly recommend everyone to also read the SharePoint 2007 and WSS 3.0 Dispose Patterns by Example post on Roger Lamb's SharePoint Developer Blog