Postfix is pretty straghtforward. Have a look at one of the howtos on www.posfix.org
I think, off the top of my head, that you'll only need to set two or three parameters in the config in the worst case for a basic setup. May even work out of the box.
If you are putting it on a Fedora box, install system-switch-mail (I think that's what it's called). This will set the necessary ssytem files to enable sendmail compatible functions to work (such as sendmail command)