Adding and removing varies depending on the distros you use.
If you use redhat or mandrake, using rpm you can add or remove programs.
Since you are newbie, I think you will be opting for RedHat, so this is the site for you --
http://www.redhat.com/docs/manuals/linux/
I think you should read this well - also you can install any package with the command ' rpm -i packagename'.