Publicity: Public Service Announcements
The Federal Communications Commission (FCC) expects radio and television stations use a certain portion of their time for public service and community announcements. These Public Service Announcements (PSA's) are announced on radio stations without charge. Whether your PSA is used, however, is at the discretion of the stations’ editors.
Send your PSA to the stations along with the press release. The most important thing to remember is that this will be read aloud, and radio-style writing is vastly different from print-style writing.
Tips: Compose a PSA on your feet rather than in front of the computer. Just speak it and then modify it. Write it down and time it, aiming for 15 seconds or 30 seconds as those are the time slots radio stations have to fill. PSA's should be written very economically and colloquially. Here is an example.