Does the sorority, or the Panhellenic Office at your school, have a webpage? You can try
www.greekpages.com and find out what sites are affiliated with your school. As for me, I filled out one of those Panhellenic Recommendation forms (my school did not require them, although the Panhellenic Alumnae Office recommended them), and the sororities contacted me upon my arrival on campus (we have deferred rush, so summer contact really wasn't an issue). As a result of deferred rush, I was able to attend study breaks and house tours in the fall, and I was able to make an educated decision about which house, if any, I wanted to join.
I am assuming that you're thinking about rushing an NPC group, right?
I'd love to talk to you more about this! Feel free to email me, or leave a post on this site!