You can go to
http://www.antennaweb.org, plug in your zip code and see what TV stations are in your area and what kind of antenna is recommended. I plugged in Bollingbrook and there are eight stations you should be able to recieve with a basic antenna, and a bunch more that may require better antennas.
For the record an antenna is an antenna - it doesn't care if the signal is HD or not. I'd get a cheap antenna from Radio Shack or wherever and give it a try. As mentioned you'll have to set your TV sets to recieve broadcast and if they're newer digital TVs you'll probably have to rescan for channels.