I have to wonder what you are actually trying to accomplish as your end goal. Using a GUI on a server is generally a bad idea since it increases your attack surface considerably, but may be justified in an intranet environment where 'better' management tools offset the extra risk.
As to your problems.
1. The 'bible' books by Chris Negus are okay, they cover most of the common server functions without trying to baffle you.
[EDIT: you might want to download the free RUTE book, a google will find it in many places]
2. VNC (or perhaps nomachine) is the closest you will find for terminal services, if you just want remote desktop access to the server, then most modern distros (including ubuntu if you install as a desktop) support a 'remote desktop' in their desktop settings.
3. ssh -X user@server
is a better option generally since you don't need to setup the forwarding or authority and the connection is securely forwarded.
[Added:If you just need easier admin of servers, there are many web based control panels, the most versatile probably being webmin, which has plugins for most server apps and usermanagement, although for hosting perhaps something like ISPconfig might be better.]