The iPhone has one default feature that drives just about everyone mad, the repeat alert. It causes the phone to give you an audio reminder of your new text message up to an additional two times if you don’t go and read it right away. I can see some cases where this many be handy, perhaps you didn’t hear the first chime because you were away from your phone, but more often it is just an annoyance. This is partially due to the fact that when you get a text message it will show up on the lock screen or on top of an application that is already running. So it is easy to just glance at it and put it back into your pocket without actually unlocking the phone and acknowledging the new text message.
So how do you go about disabling this feature? Well it’s quite simple if you’re running OS 3.0, just go into Settings then scroll down to Messages and you’ll find an option to toggle Repeat Alert off in there. You can also disable the Show Preview, Subject Field and MMS messaging in this menu as well.