Whether or not you think it's a good idea to share these kinds of tools, we should always keep in mind that it is for educational uses. Let this be a reminder that as computers get faster, it becomes easier and faster to crack passwords. That is why 2 factor authentication, biometrics and pass-phrases are becoming the recommended way to go.
That being said... go play and let us know what you think.http://ophcrack.sourceforge.net/
CISSP, MCSE, CSTA, Security+ SME