The Scripting Guy blog has a great article called Beat the Auditors which is something that most Sys Admins want to do (and in some cases it might also be in more ways than one!). The article has a powershell script that audits the computers on the network for services and accounts that may have very old passwords (or no passwords) and provides the output into a nice excel file for reporting. The article steps through the script line by line to provide assistance in understanding the script which should allow you to tweak it as required for your environment. Subscribe to the blog posts to follow the next couple of articles in the series where the script will be expanded upon and developed.
I especially liked the tagline – “if the barn doors are wide open, why look for mice holes!”