Increasingly, iPhone users have replaced their point-and-shoot cameras with the iPhones' built-in shooter. If you find yourself frequently reaching for your iPhone to capture a fleeting moment, you may want to reassign your buttons to make launching the camera faster. Here's how:
1. Launch the Settings app on your iPhone by tapping its icon.
2. Tap General.
3. Tap Home.
4. Tap Camera.
5. Turn Off iPod Controls.
Note: Step 5 prevents the display of iPod controls while music plays when you double-tap the home button.
Now, when you double-tap the Home button, you will go straight to the Camera app unless the screen is locked (in which case you'll have to use the Slide to Unlock slider and enter your passcode, if needed, before the Camera app launches).