http://www.reigndesign.com/blog/using-your-own-sqlite-database-in-android-applications/

package com.android.copydatabase;

import java.io.IOException;

import android.app.Activity;
import android.database.Cursor;
import android.database.SQLException;
import android.os.Bundle;
import android.widget.Toast;

public class MainActivity extends Activity {
	/** Called when the activity is first created. */
	@Override
	public void onCreate(Bundle savedInstanceState) {
		super.onCreate(savedInstanceState);
		setContentView(R.layout.main);

		DataBaseHelper myDbHelper = new DataBaseHelper(null);
		myDbHelper = new DataBaseHelper(this);

		try {
			myDbHelper.createDataBase();
		} catch (IOException ioe) {
			throw new Error("Unable to create database");
		}

		try {
			myDbHelper.openDataBase();
		} catch (SQLException sqle) {
			throw sqle;
		}

		myDbHelper.openDataBase();
		Cursor c = myDbHelper.getAllContacts();
		if (c.moveToFirst()) {
			do {
				DisplayContact(c);
			} while (c.moveToNext());
		}
		myDbHelper.close();

	}

	public void DisplayContact(Cursor c) {
		Toast.makeText(
				this,
				"id: " + c.getString(0) + "\n" + "Name: " + c.getString(1)
						+ "\n" + "Email: " + c.getString(2), Toast.LENGTH_LONG)
				.show();
	}
}

package com.android.copydatabase;

import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;

import android.content.Context;
import android.database.Cursor;
import android.database.SQLException;
import android.database.sqlite.SQLiteDatabase;
import android.database.sqlite.SQLiteException;
import android.database.sqlite.SQLiteOpenHelper;

public class DataBaseHelper extends SQLiteOpenHelper{
 
    //The Android's default system path of your application database.
    private static String DB_PATH = "/data/data/com.android.copydatabase/databases/"; 
    private static String DB_NAME = "myDBName";
    private SQLiteDatabase myDataBase; 
    private final Context myContext;
    private static String DB_IN = "mydb";
    public static final String KEY_ROWID = "_id";
    public static final String KEY_NAME = "name";
    public static final String KEY_EMAIL = "email";
    private static final String DATABASE_TABLE = "contacts";
    
    /**
     * Constructor
     * Takes and keeps a reference of the passed context in order to access to the application assets and resources.
     * @param context
     */
    public DataBaseHelper(Context context) {
    	super(context, DB_NAME, null, 1);
        this.myContext = context;
    }	
 
  /**
     * Creates a empty database on the system and rewrites it with your own database.
     * */
    public void createDataBase() throws IOException{
    	boolean dbExist = checkDataBase();
 
    	if(dbExist){
    		//do nothing - database already exist
    	}else{
    		//By calling this method and empty database will be created into the default system path
               //of your application so we are gonna be able to overwrite that database with our database.
        	this.getReadableDatabase();
        	try {
    			copyDataBase();
    		} catch (IOException e) {
        		throw new Error("Error copying database");
        	}
    	}
    }
 
    /**
     * Check if the database already exist to avoid re-copying the file each time you open the application.
     * @return true if it exists, false if it doesn't
     */
    private boolean checkDataBase(){
    	SQLiteDatabase checkDB = null;
    	try{
    		String myPath = DB_PATH + DB_NAME;
    		checkDB = SQLiteDatabase.openDatabase(myPath, null, SQLiteDatabase.OPEN_READONLY);
    	}catch(SQLiteException e){
    		//database does't exist yet.
    	} 
    	if(checkDB != null){
    		checkDB.close();
    	}
 
    	return checkDB != null ? true : false;
    }
 
    /**
     * Copies your database from your local assets-folder to the just created empty database in the
     * system folder, from where it can be accessed and handled.
     * This is done by transfering bytestream.
     * */
    private void copyDataBase() throws IOException{ 
    	//Open your local db as the input stream
    	InputStream myInput = myContext.getAssets().open(DB_IN);
 
    	// Path to the just created empty db
    	String outFileName = DB_PATH + DB_NAME;
 
    	//Open the empty db as the output stream
    	OutputStream myOutput = new FileOutputStream(outFileName);
 
    	//transfer bytes from the inputfile to the outputfile
    	byte[] buffer = new byte[1024];
    	int length;
    	while ((length = myInput.read(buffer))>0){
    		myOutput.write(buffer, 0, length);
    	}
 
    	//Close the streams
    	myOutput.flush();
    	myOutput.close();
    	myInput.close();
    }
 
    public void openDataBase() throws SQLException{
    	//Open the database
        String myPath = DB_PATH + DB_NAME;
    	myDataBase = SQLiteDatabase.openDatabase(myPath, null, SQLiteDatabase.OPEN_READONLY);
    }
 
    @Override
	public synchronized void close() {
    	    if(myDataBase != null)
    		    myDataBase.close();
    	    super.close();
	}
 
    public Cursor getAllContacts()
    {
        return myDataBase.query(DATABASE_TABLE, new String[] {KEY_ROWID, KEY_NAME,
                KEY_EMAIL}, null, null, null, null, null);
    }
    
	@Override
	public void onCreate(SQLiteDatabase db) {
 
	}
 
	@Override
	public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
 
	}
 
        // Add your public helper methods to access and get content from the database.
       // You could return cursors by doing "return myDataBase.query(....)" so it'd be easy
       // to you to create adapters for your views.
 
}