Instant message service system and mobile, and service method thereof

The instant message service system and a mobile communication terminal, and a service method is disclosed. Instant message service system according to the present invention according to the instant messaging service system for providing an instant message service in the mobile communication terminal is installed an instant messenger, and from the mobile terminal receives the information on the instant messenger to store in the database information storage unit; And the mobile when the terminal receives the subscribe request signal from the mobile communication comprising: providing information for providing information about a contact corresponding to said instant messenger installed in the terminal unit, the instant messenger is installed in the mobile terminal the possible transmission of force messages determine whether availability using an instant message to the contact, and on the basis of the information received from the information provider, if the contact is determined as a dialog out using the instant messenger determining whether features. IM, SMS, MMS, integration, dialogue groups, contacts, forced Message