The WiFi, GPRS shield, Ethernet Shield are very expensive for a newbie, so to reduce this cost I tried to combine different methods and use the common things that are available in the house and use it to control arduino over Internet. This is how I did.

Step 1: Material Required

For this project we require-
1)arduino
2)otg enabled android phone
3)otg cable
4)PC/laptop(to program arduino and control it wirelessly. Should have arduino ide installed)
5)USB cable type A to type the arduino have.
6)and an internet connection on phone and PC/laptop of course.

Step 2: Applications to Be Installed

Install the following applications on your phone from play store-
1)Teamviewer host
2)Arduino droid

Step 3: Code

This is a test code for an example which turns the led on pin 13 on on sending 1 and off on sending 0 .

#define led 13
void setup() {

// put your setup code here, to run once:

pinMode(led, OUTPUT);

Serial.begin(9600);

digitalWrite(led, HIGH);

delay(1000);

digitalWrite(led, LOW); }

void loop() {

// put your main code here, to run repeatedly:

if(Serial available() > 0){

if(Serial.read() == '0')digitalWrite(led, LOW);

if(Serial.read() == '1')digitalWrite(led, HIGH); }

delay(100);

}

upload this code to arduino via ide.

serialLed.ino
Download

Step 4: Connections

Connect arduino to USB cable, USB cable to otg cable and otg cable to the phone.
Now open the app team viewer host app on phone and login.

Step 5: Control Over Internet!!!

login to teamviewer website via PC laptop and then open your device and now you can control your phone.
open arduino droid app on your phone, it will take some time to load first time. press menu button, touch actions, and then monitor. Change baud rate to 9600 and then just send series of 0 and 1 the number of times you want and you can make led blink at different or same interval via internet!