As someone who is an Ole Miss alumna, sorority alumna, and I work on campus, I would read over what the new Panhellenic Website says.
http://www.olemiss.edu/orgs/panhelle...l/Welcome.html
Also, keep in mind that recruitment is late in October this year so you will have been on campus for almost 8 weeks before recruitment starts, so you'll have plenty of time to buy clothing. Furthrmore, late October in Mississippi can be anything from warm and humid to cool and rainy. So, I wouldn't go out and buy anything just yet!
There is picture when you click on the recruitment link and it has 3 pictures. Those are the 3 pictures of what they suggest you wear for each round of recruitment. However, your Gamma Chi's (Recruitment Counselors) will inform you in August when recruitment meetings begin for PNMs on what to wear.
Good luck!