An application development platform enables applications to be created easily for, e.g., mobile devices that have short-range wireless communication capability. The development platform exposes a carefully chosen core set of services through an API. Each of the applications can broadcast its services to local and remote devices. Message delivery between devices is guaranteed even for messages that cannot be delivered directly by local short-range wireless transmission. Message delivery through other channels, including the Internet, can occur transparently to the user. Each device can be associated with an "owner", which can be a person or a entity. Services can be customized to the owner based on stored information that maps owners to devices. Information associated with each of the owners of devices can be stored centrally and used in connection with providing the services at each of the mobile devices. Virtual GPS capabilities can be provided for mobile devices that do not have GPS chips.