earlier today i finally updated my 2g ipod touch for the iOS 4 update.i was so excited, but, my ipod doesn't seem very different. please tell me some things that were worth the update that came with the update. and how do you change the background. not when you click the on button to turn it off the sleep, but the background behind the apps.. i was very much excited for that feature. PLEASE HELP ME ASAP!!!!!!! THANK YOU!