Comment: My half-shilling (Score 1) 528
I currently am an assistant to the systems manager at a department in my university, and we document stuff all the time for the very reason you bring up. Really, the main things to document are:
- Server setup/maintenance
- Network layout/settings
- Solutions for important/frequently occurring issues
- If you install computers using an image, document how this is done (we use Ghost where I work)
- Descriptions of software used on network clients
There are many other things that you can document, of course. But the above list contains what I consider to be most crucial.