[jyl]

First try rebooting it. Hold down power and home buttons until the screen goes blank. Ignore the "slide to power off" screen. Then press power button and after a while you'll see the apple logo and it will restart.

If that's doesn't work, then try other things.

BTW, text notification problems could be ATT related. I had a problem with my visual voicemail - messages wouldn't show up - and they had to make some fix on their end. I don't know exactly what, but at some point you might end up calling them.