A mobile telephone terminal provides a user with a selectable option to transfer a telephone call to an instant messaging session and to transfer an instant messaging session to a telephone call. A presence attribute indicator for a first party is displayed with an entry associated with the telephone number of the first party. A user has a selectable option for initiating instant messaging with the party. The mobile telephone provides a customized menu of selectable options for initiating communication. The menu is dependent upon received presence attribute information. A calendar application can store the content of an instant messaging dialog in an appointment record. When an application accesses a stored telephone number of a party the stored instant messaging address of that party is automatically accessed and when the application accesses a stored instant messaging address of a party, the stored telephone number of that party is automatically accessed.