irishpipes has established a fairly comprehensive Fall recruitment thread here:
http://www.greekchat.com/gcforums/sh...ad.php?t=86934
It doesn't appear that the information has been publicly distributed yet. (Though there
is a link to a PDF file of a Panhellenic calendar on the Greek Affairs website which says that formal recruitment is Aug 11th-16th, with a recruitment wrap-up...whatever that is...on Aug 29th.)
I would second the idea that you should contact the Greek Affairs office directly - most large universities send a mailer to incoming freshmen over the summer which contains the registration form and other necessary info. If you want the information before that mailer goes out or if you just want to make sure that you are on the mailing list for any materials, the Greek Affairs office is going to be the one who can assist you with that.
If you have general questions about recruitment (do I need recommendation letters? what should I wear? etc.), there are a wealth of threads here which detail that info - you might also want to browse those s you have time. If you do a search for Iowa State, you might also find specific information to that campus too. (I know we've had at least one or two ISU Greek folks on GC...)
Good luck!