Today, a new tool SharePoint Dispose Checker Tool has been released at MSDN for checking your code against incorrect processing of IDisposable objects like. SPSite and SPWeb. This tool checks your assembly and identify potential problems of not disposing these objects.
You can download SharePoint Dispose Checker Tool from here
and here is the great article from Paul Andrew (Microsoft Technical Product Manager for the SharePoint Developer Platform) about best practices and how to use this tool.
