Step 1. Turn off your iPhone.

Step 2. Hold down the power and home button.

Step 3. When you see the Apple logo, release the power button but continue holding the home button down.

Step 4. Open iTunes and wait for it to tell you that its in restore mode.

Alternative Method:

Step 1. Connect iphone to USB then listen to the sound when it connect and disconnect.

Step 2. Hold the home and power buttons until hear the disconnect sound then release power button.

Step 3. Wait until you hear another sound then release home button.

About Me: Anish Kumar:
Mac OS X software development is my bread winner with over 6 years of experience. Expertise in Color Management, TWAIN Scanner drivers on Mac OS X, Photoshop Filter and Import Plugin development on Mac OS X, iPhone. As an hobby I love to work on PHP, Flex, AIR, Photoshop. Check the 'About' page for more.