Well, first off the "tty1" means you are logged in to, say, terminal 1. Try pressing ctrl + alt together --> then press F2. Alternativley you can do the same but instead of F2 use F3 and F4 so on and so forth. These are your multi-user sessions. Neat huh?
Next, the terminal is telling you that you have mail and I think it is in the /var/log directory where you will find your mail however this is an area where I am weak so perhaps another LQ member will be more insightful.
lastly, the "[root@localhost root]#" means you're logged-in as root (the most powerful user) and the localhost is the default machine name Redhat has given your server.
You can change all of these and I would recommend not logging in as root. Try creating a normal user account and if need be su -l to root to perform any rootly duties.
Here is a good place to start: http://www.justlinux.com/nhf
and is by no means the best or worst but as you use the system more you will find your way around little by little.
Redhat is a good starting Linux Platform but don't forget to try out different distro's to find one you like. I started on RH and then moved over to Slackware and fell in love. To each their own!
Hope this helps and enjoy Linux!