There are a couple ways you can go about this.
-If there is a location, studio or a gym which you are interested working at, either visit them online to see if they have any openings or visit them in person.
I know there are many places in Chicago where you could look for a position. I’m not sure what your experience is, but here is a link that might also help:
I hope this helps.
Harris’s response is great, lots of good contacts. When I was in the business of hiring instructors and trainers, I was always most impressed when an interested instructor would make an appointment to meet with me, then show up, on time, ready to demonstrate his/her skills in working with potential students and/or clients.
Just an interviewing tip… look the part. Come in wearing a cycle jersey and shorts, clipless shoes (for whatever the bikes they have support), and ready to give a demo ride as part of your audition. My GM friend says she laughs every time someone shows up in business casual for a fitness position interview when they know a class demo/audition is required.