I've compiled some info on how to become a police officer in Chicago. Of course, this is how the training is currently, but hopefully it hasn't changed too much in the last years.
I mostly copy/pasted from
Chicago Police Officer Career Information The minimum age requirement is 21 years of age. Residency in the City of Chicago is required of all employees, but residency within Chicago is not required during the application and testing process.
Applicants must have at least 60 semester (90 quarter) hours of credit from an accredited college or university. Also acceptable are applicants with four years of continuous active duty in the armed forces of the United States.
The hiring process begins by passing a written exam. The remaining steps include a physical fitness test, drug screening, psychological test, background investigation and a medical examination.
Successful applicants who are hired as Chicago Police Officers begin their careers at the Training Academy as Probationary Police Officers (PPOs).
Academy training consists of the 480 hour minimum course required by the Illinois Governmental Law Enforcement Training Board and 300 hours the Chicago Police Department includes to augment the basic training course.
Course topics include Human Behavior, Criminal Law, Traffic Law, Firearms and Drill Training, Physical Training, Department Administrative Systems and Operations, Policy and Procedures, Report Writing, Crime Investigation Procedures, Safety Practices, and many more.
Successful completion of the course prepares the recruit for the State of Illinois Certificate Examination and the next phase of training - Field Evaluation. Each probationary police officer must complete an 18-month probation period.