Here's my 2 cents.... Windows server is an umbrella for a variety of different server roles. You don't have to support every single role in order to support Windows Server...ie You don't have to know the fax server role if all you want to support is Active Directory, although learning the DNS role is required for AD to run.. DHCP can be setup somewhere else like on a router, although it was recommended to me to keep the DHCP role on the server to keep the system "tight".
I learned a lot of Server 2003 in my home by installing it on a system where parts were conjured up from the scrape heap..You can even install it in a VM on a machine with enough computing power. You don't need fancy hardware to learn the basics of the software, although you'll probably get a better experience installing it on real server hardware. For instance, I learned the Active Directory role on that junky old thing, although I don't know AD as well as I'd like at this point. Once you get a feel for setting up DNS and DHCP on the server, ADD the AD role and add some user accounts and computer accounts (they are different things) and practice logging them into the domain, whatever it is that you name it...ie testDomain.local. You'll probably get a bunch of error messages when first trying to long in your clients, but troubleshooting the log in problems is what helps you get a feel for how it works. ...You can verify that DNS and DHCP are working and being served from your Windows Server by doing an IPCONFIG /ALL from the client computer and checking that the client computer's DNS server and DHCP server ip address are both the IP address of the Windows server. You'll probably have to do ipconfig /release and /renew a few times before you get it right. That's one of problems I had to get around when trying to log client into the domain the first few times. Once you're able to get client's logged in, start setting up some "security groups" for sharing network resources, and setting up permissions on the shared resources. Then once you get that licked start adding some group policies, ..and so on and so forth... Start with a foundation and build it up...
I'm not supporting Server at the onset of my business because although I've gotten a good feel for it, I haven't use it enough to feel comfortable advertising support for it, and there's a few more things I need to learn about it.
