A system and method provide calling and called terminals with multimedia alerting signals such as a ringtone and ringback tone. When desiring to receive first multimedia portal contents as a multimedia alerting signal, the calling terminal presets the first multimedia portal contents and makes a call connection setup request. When desiring to provide second multimedia portal contents as a ringback tone, a called terminal presets the second multimedia portal contents and notifies that the ringtone and ringback tone are set. A Personal Internet Protocol Multimedia Subsystem (IMS) Portal (PIP) server receives call connection setup-related signals from the calling and called terminals, decides to provide particular multimedia portal contents as the ringback tone according to a predefined priority decision criterion when the calling and called terminals set the multimedia portal contents, and provides the set multimedia portal contents.