Hello...just got an iPhone 3g last week. already loaded some songs from iTunes. the question is: how do i DELETE songs? when i plug iPhone into my computer, the songs are all grayed-out; they don't allow you to click on them to delete (the way i can on my ipod)! Is there some special trick I need to know? Or does this mean any song you load on iPhone, you can't change your mind? HELP!