You file it with the Clerk of the City of Chicago. The link is: http://www.chicityclerk.com/claims/mod_mvform.html

Note that you should fill out the form online and then print it out. If you print out the form, you will need to type in the data anyway - handwritten is not permitted. You need the police report before you fill out the form since you need to include the police report number on it.

I think that you will need to stop into a police station to get the report. It can be any station. You should bring in your drivers license and your insurance card. If your VIN is not on the insurance card, you should bring in your registration as well. It took me less than 10 minutes from the time I got in the station until the time I left.

Good luck!

3/28/08: Updated to include the correct form with the city. Originally I had posted the property damage form link when what is really needed is the motor vehicle damage form. Sorry about that!