When taking a picture, if the subject is backlit, the built in flash will automatically pop up when the shutter release button is lightly pressed down (not pressed down all the way).  When the flash is ready to fire, a lightening like symbol will appear in the viewfinder on the bottom, right hand side.  Once you see that symbol, you can compose, focus, and take the picture by fully depressing the shutter release button.  Depending on the shooting conditions, the flash can illuminate objects up to 28 feet away.
                                                                    
Taking a picture with out the flash in dark conditions:
                    - If you wish to take a picture with out the flash in conditions where it would normally automatically be used, simply close the flash  (just by pressing it back down into its original position) while lightly pressing the shutter release button (not pressing it down completely). 
                   - As long as the shutter release button is kept lightly pressed, the flash will be canceled for any following pictures as well.  Once you have removed you finger from the shutter release button, the flash will pop up again and begin to charge when the shutter release button is pressed again.