I am a president of a Fraternity at Iowa State, so I can give you a little more specific information.
Unfortunately Iowa State's webpage takes some getting used to before you can navigate it well. The Greek website is
http://www.greek.iastate.edu/
As for Greek life on campus, Iowa State has a tradition Greek life. My house has been on campus for over 100 years. There are 29 Fraternities and 15 sororities. We are very active on campus and have a good relationship with our university. If you are an incoming freshmen you will need to join formal rush in the fall and you will get to meet all of the houses. If you want to get in touch with the sororities earlier, you can come into town for Greek Week. During Greek Week we invite High School students to come stay at Fraternities and Sororities for the weekend. It's a great even and you can get a feel of Greek life.
If you want any more information just use the Greek website to get in contact with more people on the campus!
Hope to see you around next year!