From Forum Nokia Wiki

Short Message Service (SMS) is a service included in mobile devices to send and receive text (or binary) messages. It was originally developed in the GSM standard but today is available in many wireless networks.

To develop applications and games (like multiplayer ones) that uses SMS you can use Java ME with Wireless Messaging API (WMA) or Symbian C++.

S60 Messaging Application Services provide the following APIs:

• MMS

The MMS Client MTM API allows your application to construct and send MMS

messages, and to access the properties and fields of a message.

• Instant messaging (IM) APIs

The IM APIs allow you to add IM capabilities to your application.

• BIO Messaging

The Plug-in Bio Control API classes allow you to register new viewer

components for Smart Messaging viewer Bio message types.

• Send UI API

The Send UI API allows you to add interactive messaging capabilities to your applications. These services are device dependant but typically include, SMS, MMS, Email, Bluetooth and Infrared. In addition to these MTM-based options, services based on the ECom architecture may be also be available and could include sending meeting requests or uploading MMS messages.