I think you'll need to give us more info on what exactly you're trying to achieve? I assume you want to learn about Server OS and Networking (rather than SQL). If this is the case, Small Business Server is a very good introduction with lots of wizards and it includes Exchange.
Well....currently I am in the IT department for a large corporation.
I mostly work with the computer hardware (Printers, installations, troubleshooting)
but I really want to learn more about how its all being run.
At the house I have 2 desktops and 3 laptops using a
wireless router to access the internet. What can I set up to try to get
some experience?