Generic messaging and protocols are provided for handset-to-handset communications in accordance with, for example, the Secure User Plane Location (SUPL) protocol. A mobile device initiates a geolocation-related session with a second mobile device by sending a message, including a payload, to a server (e.g., an H-SLP server) over a network. A data connection is the established between the second mobile device and the server in response to the message. A message, including the payload, is then sent to the second mobile device. The payload may include geolocation (e.g., GPS) information, such that two mobile devices may collaboratively share information regarding the other's geographical location.