What is exactly the subject ?
You have plenty of possible subject, I'll juste list some common themes, but without precise subject I can be all wrong :
virtualisation : xen, KVM...
security : built-in functionnalities (root accout, kernel architecture, software installation, folder rights...), best practices, implementing software (kerberos, clamAV + squid...)
free software : how it works ? what are the drawbacks ? what are the advantages ?
linux interoperability with mac / windows / BSD and how to integrate linux in a windows server controled environnement.
You can also refer to this site tutorials like ISPconfig.
How many time do you have to do so ?
I you give me a more precise subject, I'll try to give you subjects which will suit you more if I can.