A method of enabling a terminal 1,2 coupled to a GSTN 10 to join an Internet based presence service facilitated by a presence server 6. The method comprises establishing a telephone connection between said terminal 1,2 and an intermediate server 4 via the GSTN 10, as a result of said connection, establishing a proxy entity corresponding to said terminal 1,2 at said intermediate server 4 and registering the proxy entity with the presence server 6 via the Internet, and exchanging presence service messages between the presence server 6 and the proxy entity at the intermediate server 4 via the Internet and between the proxy entity and said terminal 1,2 via the GSTN network 10.