Ahh...welcome to the light side of the force! (or is it dark side? I can never remember
).
Linux is a very different experience from Windows, but once you get used to all the little quirks and such, it's as natural as opening MS Office (but w/out the bloat
).
So far your questions are not dumb at all, as RH should recognize your Network card from the install. First thing you'll need to do is login as root.
(To answer your question, switching to root requires the use of the command 'su'. Just type it in and enter the password. to get out, tpe exit. Note that this does NOT carry over into Xwindows, and for that you'll either have to log in as root, or you enter the password when it asks. If you have no idea what 'su and 'exit are for, get into the console/terminal/DOS Prompt/whatever teh heck you kids call it today)
Here's a tutorial for RH7.3 (the version you are using, right?) on setting up the network:
http://www.ncsu.edu/resnet/pages/setup/rh8.php
Have fun!
To answer your other question, Red Hat is not the Linux I would have started out with, but it IS the first real taste of Linux I ever had. I reccomend you check out Mandrake, but only once you have a better machine. There are many, many distributions, check out a good sampling at:
www.linuxiso.org 
Linear Mode
