Well, if you're simply talking about storing login profiles centrally, you can set up a Windows 2000 Server or Advanced Server as a domain controller, and have your win2k clients log on to the domain, and they will pull their profiles from the server.
As to actually booting the clients from the server, I don't know if that's even possible with Windows, but I know it can be done with linux, although it's very hard to acomplish (at least for Linux non-experts like yours truly) 😉