1、main.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent"
    android:orientation="vertical" >

    <TextView
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        android:text="手机号码" />

    <EditText
        android:id="@+id/numET"
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        android:inputType="phone" />

    <TextView
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        android:text="短信内容" />

    <EditText
        android:id="@+id/contentET"
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        android:inputType="textMultiLine"
        android:lines="3" />

    <Button
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:onClick="hello"
        android:text="发送短信" />

</LinearLayout>

2、MainActivity

package com.example.smstest;

import java.util.List;

import android.os.Bundle;
import android.app.Activity;
import android.telephony.SmsManager;
import android.view.Menu;
import android.view.View;
import android.widget.EditText;
import android.widget.Toast;

public class MainActivity extends Activity {
	private EditText et_num;
	private EditText et_content;
	
	
	@Override
	protected void onCreate(Bundle savedInstanceState) {
		super.onCreate(savedInstanceState);
		setContentView(R.layout.main);
		
		et_num = (EditText) findViewById(R.id.numET);
		et_content = (EditText) findViewById(R.id.contentET);
		
		
	}

	public void hello(View view){
		String num = et_num.getText().toString();
		String content = et_content.getText().toString();
		
		/**
		 * 以下是发短信的核心代码
		 */
		SmsManager smsManager = SmsManager.getDefault();
		List<String> list = smsManager.divideMessage(content);//分割短信内容.用于处理一条短信太长的情况...
		for(String str : list){
			smsManager.sendTextMessage(num, null, str, null, null);
		}
		
		Toast.makeText(this, "hello sms", 1).show();
	}
	@Override
	public boolean onCreateOptionsMenu(Menu menu) {
		// Inflate the menu; this adds items to the action bar if it is present.
		getMenuInflater().inflate(R.menu.main, menu);
		return true;
	}

}

3、AndroidManifest.xml

 <uses-permission android:name="android.permission.SEND_SMS"/>

源码下载：http://download.csdn.net/detail/caihongshijie6/7600765