The iPhone 4 / iPad 2 have enhanced camera functionality (FYI: the predecessor models had only one camera, while the new devices now actually have two: forward facing and rear facing).  The new cameras also have functionalities the old one did not, like:

Camera Flash
Open the Camera app; there’s a flash icon at the top left of the screen (looks like a lightning bolt).

Sometimes our iPad 2 or iPhone 4 has 10 or more apps suspended but still running, draining battery life.  To close the apps, double click on the home button until the Shortcut Menu appears.  Now tap and hold on any shortcut icon until they begin to wiggle.  You’ll notice a red bar appear at the top left of each app that’s running.  Click on that bar to close the app.  It will shut it down and unpin it from the Shortcut Menu.

Want to save battery life on your iPad 2 or iPhone 4?  Switch up the data push frequency.