I just bought a 3G iPod Touch 32GB (my first iPod) running iOS4. I am concerned about leaving too many apps open in the background reducing the battery life. Everything I have found online says to hold the home button for 5 seconds, but when I do this I just get a new screen that says "Voice Control". Any thoughts on how to actually close the app and not just minimize it? I have also tried 1) powering down and restarting, and 2) holding home button and power button simultaneously for 5 seconds with no success.