I ran across a great tool by MikroTik which will map your network and then provide service level monitoring and alerts all for free. Check this out in the "Free Security Tools" > "Network Tools" section.
This Access database is intended to help keep track of servers (Windows, Linux, & Unix). The database has sections for hardware, applications, users, and system configuration. This is a handy utility that I built years ago to help track around 100 servers. There is no reporting built into the tool yet.