Most people by now have heard of sidejacking. That's where a bad person (and a laptop) connect to one of the unencrypted wireless access points at school, and listen for the cookies of other students who are also connected and browsing the web. It's trivial to accomplish, and there is no easy way to detect it. It has been publicized as being the method used to hack your facebook or email. This hack can easily lead to partial or full identity theft.
What some people don't understand is that security software can't and won't help you. The only thing you can do is make the effort to only connect to encrypted wireless (uwo-secure).
Another misconception is that you're only at risk with facebook and email. This is dangerously wrong. Using open wireless at UWO can also lead to compromising your UWO Career Central, UWO Student Central, UWO WebCT Owl, UWO Sakai, and any other passworded site.
If you don't know much about computers, you can take your laptop to ITS and they'll give you a hand!