Each campus handles recruitment differently. Some hold formal recruitment the week before schools starts in the fall, some just after during a (verrrry fullllll weekend), some spread it over several weekends after school starts, and some hold deferred recruitment either just before school starts back in Jan. or just after. So what to expect differs from campus to campus.
Check out the web page for the school and see if they have a greek life page. Sometimes you have to use the search feature and look up panhellenic or sorority. Some - for example:
http://www.union.arizona.edu/csil/greek/index.php (Arizona)
http://www.nmsu.edu/Campus_Life/Stud...tml/index.html (New Mexico State)
http://www.auburn.edu/panhellenic/ind2.html (Auburn)
have really extensive web pages with lots of information about greek life and some don't.
If you tell us where you'll be going, there may be someone from that campus or familar with that campus that can more accurately answer your questions.
Also, if you haven't already .. you might try reading through the threads from women who went through recruitment last fall.
Good luck!!