Butler SOS has matured quite a bit during past couple of years, with latest additions being fine-grained monitoring of what users are connected to what servers.
Opens up for various interesting use cases, including notification to users before server restarts etc.
Starting today that site is the goto-place for everything Butler SOS related.
The site contains both installation and configuration instructions, as well as a (hopefully growing) set of examples on how Butler SOS can be used in various way.
Make sure to check out the blog section of that site too!