My oh my...
It is not easy to learn Linux it takes a lot of time especially security. Linux is definitely better then NT4, but you'll have to reteach yourself. And get used to the fact that after every program installation you don't actually have to reboot your machine...
This is what I suggest...
Go to google.com and search for Trinity OS - it is a terrific guide by David Ranch on Linux security
Go to www.linuxdoc.org (Linux docmentation project). This site has full blown books on networking, servers, and etc. for free, plus a complete list of howtos.
With patience and dedication you'll be a linux wiz, and you'll never go back to windows...
Di