After the much anticipated release of the SPDisposeCheck from Microsoft via codeplex (http://blogs.msdn.com/sharepoint/archive/2009/01/29/spdisposecheck-released.aspx), this would make a pretty cool External Tool for Visual Studio  Here how to set it up http://www.sharepointblogs.com/teameli/archive/2009/02/20/using-spdisposecheck-in-visual-studio.aspx