I've never tried the school route personally for casting. The Dallas-Fort Worth Metroplex is large enough that Craigslist usually returns more than enough. Chicago is even bigger, you should be fine.
One note, I have an email that's only for craigslist and I only check it when I have an Ad out. When you put an email there, you WILL get spammed. Just part of the game.
Forms: Actors need audition info (time and location) and sides. Sides are a page or three of the script that you think accurately tests the character they're auditioning for. At the audition, have a camera going as a screen test, someone sitting in the Lobby (we like to sign them in, and if it's a call back or what we have them sign the waiver too allowing us to use their image in the project- some people flake out after all so if they don't sign, they don't audition), a pot of coffee and some sides printed out. Actors will bring their headshot and resume with them. When ready, you'll bring someone into the room and you and your casting director or producer or other key person will listen and watch as they read the lines. Have someone else read the opposite characters lines to them.
Small talk is nice, make them feel comfortable but don't waste time. After they do the lines once, have them change something. Even if they play the part better than you could have imagined, give them direction and see how they do with it. If they can't take direction, they probably aren't a good fit for the project.
I forgot to mention scheduling. At the free level, it's really nice to schedule the audition for actors instead of having 30 people show up at 9AM and wait. Wade through the headshots and resumes of the emails you get from craigslist. Find the ones that could fit the part, call them and schedule them. What I like to do is plan for about 8 minutes each. That works for me, some people want 3, some want 15. I also double/triple book appointments. People are flaky, internet people more so. Especially with no pay on the line, if the actor is tired or in a bad mood audition day or a friend wants to go to the movies, they'll probably flake out and not give you a call. Sometimes 2 people show up at the same time. Waiting 10 minutes is still better than waiting 2 hours when everyone shows at once.
Make notes, talk with your producer after they leave and bring the next person in. Afterwards you can watch the tape and see what they look like in camera and then you narrow down your pool, good to go!
And yes, unless your friends are actually actors, don't cast them
