If you are looking for tool to assist you with taking an inventory of both computer hardware and software on your network, then give a good look at OCS Inventory. This free, open source tool boasts many features, including: 

• Windows, Unix and Mac detection.
• Lightweight on system resources.
• Easily deployable through scripts. 
• Web based interface.
• Query’able and extendable through web services and an API.

If you have ever been faced with trying to do an audit on a large network, you know having a tool to simply the process is almost a requirement. For this reason, OSC Inventory deserves a fair look.