First things first, a sorority is not just a place to live. My apologies if this is something you are aware of, but the way you worded your first sentences leads me to believe otherwise.
Based on your questions, it sounds like you could benefit from this thread:
http://www.greekchat.com/gcforums/sh...ad.php?t=54403
It focuses heavily on recruitment, but there is very useful information for someone who is just getting acquainted with Greek life.
Take some time and read through, I think it will be very helpful for you!