A resume is essential if you are looking for employment. Past work history, periods of unemployment, names and addresses of former employers, references, special qualifications, special licenses, and education should be listed.
Always be truthful on your resume -- the job you are looking for requires complete honesty since you will be responsible for keeping other people honest. If the prospective employer does a background check, as he should, having a totally honest resume will be a real benefit since a large number of people exaggerate or lie and most interviewers assume you are at least "puffing" your experience.
It is also advisable to have taken, or be taking, college courses in police science and sociology-type subjects to be more effective in dealing with the public. You will be representing your employer and should present a professional and knowlegable presence.
Free sample resumes, cover letters, and writing tips can be found at:
businessballs.com/resume.htm -- tips
riseway.com/free-resumes.html -- tips
Other sites provide a resume-writing service for a fee:
free-resume-tips.com/ -- free tips, pay for resume