Following my blogcast in February and subsequently posting the markShareforABDE tool for download a few days later, the official download is now available. There's a GUI thrown in as well for good measure for those who try to steer clear of the command prompt. The landing page for the download links is here. There are three versions depending on your processor architecture - i386, AMD64 or IA64. In a nutshell, Access based enumeration (previously known as Access Based Directory Enumeration) hides files and folders for which users do not have rights to see on network shares.
Remember though, Access Based (Directory) Enumeration only works on servers running Windows Server 2003 SP1.