First, go to "Mail, Contacts, Calendars" in your Settings application. Add Account. Other. Under Contacts, select "Add LDAP Account".
The server name is going to be "directory.cornell.edu", and the description can be whatever you want to appear in your Contacts application. No user name or password is required. I didn't have luck with connecting via SSL. Continue the setup without SSL.
You can hit the Save button from here. Just in case though, the Search Settings at the bottom should be automatically filled out to be "o=cornell university,c=us". The Search Scope is "subtree". This is probably fine for most cases.