From Forum Nokia Wiki

Compatibility: Flash Lite: 1.1, 2.x

Sending SMS/MMS

• To send SMS or MMS you have to use the GetURL() function with this statement in parameter:

"sms:aNumber?body=A Message" or "mms:aNumber?body=A Message"

• An example:

myNumber = "4815162342";
myMessage = "Hi, This is my message";
 
getURL("sms:" add myNumber add "?body=" add myText); //Send a SMS
 
/* 
getURL("mms:" add myNumber add "?body=" add myText); //Send a MMS
*/

• In S60 phones, this function will not immediately send the message but open the built-in SMS/MMS editor filled with the given parameters.

Checking SMS/MMS capabilities

You can check if Flash Lite can send SMS or MMS by using this numerical variables:

• _capSMS: Set to 1 if Flash Lite can send SMS. Otherwise, this variable is undefined.
• _capMMS: Set to 1 if Flash Lite can send MMS. Otherwise, this variable is undefined.
• In Flash Lite 2.x, it is recommended to use System.capabilities.hasSMS and System.capabilities.hasMMS variables.

An example:

if(_capMMS)
{
getURL("mms:4815162342?body=Hi, This is my message"); //Send a MMS
}

Download

You can download an example with source code here:
Sending SMS/MMS example 240*320 (swf + fla)