A note on frequencies for scanner/listening to public services: public services such as police, fire and rescue, utilities, etc., once transmitted using analog signals and could be received on most scanners and some amateur radios. As technology has advanced, many public service agencies around the country - and in our area - have either switched to digital or encrypted communications or are in the process of doing so.
The best listing of local public service frequencies we have found for our area is at RadioReference.com. Just be aware that some frequencies may be encrypted, in which case you will not be able to receive them no matter what scanner or radio you use.