Read & experiment. I'd recommend picking up Mastering Windows 2000 Server by Mark Minasi. It's good for the beginner or the veteran. Starts simple on his explainations but gets into a lot of detail. Also pretty easy to read as far as technical books go.
If you can, get your hands on a couple PCs, a copy of Win2k Pro, and a copy of Win2k server or advanced server (evaluation maybe? - I think if you order one off MS's webpage shipping & handling is I think all you pay). Install yourself a server and a client and then you can do what's being described in the book(s).
Don't expect to be able to jump deep into the industry quickly. Most places won't hire somebody without IT experience (even if they're an MCSA/MCSE). Don't be afraid to get a tech support or other entry-level job until you've got some experience under your belt. Marc Creviere