Mobile telephone user route mapping services and coverage area warning services and systems for providing such services are provided. Origination location and destination location information is entered, and a route between the locations along which wireless telephone system coverage is available is returned. If the returned route is less preferable than another possible route along which there are areas of poor coverage or no coverage, the provider of the wireless telephone system is informed, and this information can be used to identify areas in which improved coverage would most benefit mobile telephone users. A warning may also be provided to inform the parties to a call that a participant using a mobile telephone is about to enter an area of poor coverage or of no coverage. The described services may be offered in return for a fee paid to the service provider.