Have you tried some basic troubleshooting at all?
First, go into Settings and toggle Airplane mode for about 10 seconds, and try it again. If it still doesn't work, try these:
Power cycle:
Hold the Sleep/Wake button (on top) until you see a red slider that says "Slide to Power Off." Drag the slider across the screen to allow the device to power off. Wait 10 seconds, and then press that button again to turn it back on.
Reset:
Press and hold the Sleep/Wake button (on the top) and the Home button (on the front) together for about 10 seconds, until you see an Apple logo. (You may see a red slider prior to the Apple, that's OK, but just ignore it). When you see the Apple you can let go, and wait for it to restart itself.
CG
First, go into Settings and toggle Airplane mode for about 10 seconds, and try it again. If it still doesn't work, try these:
Power cycle:
Hold the Sleep/Wake button (on top) until you see a red slider that says "Slide to Power Off." Drag the slider across the screen to allow the device to power off. Wait 10 seconds, and then press that button again to turn it back on.
Reset:
Press and hold the Sleep/Wake button (on the top) and the Home button (on the front) together for about 10 seconds, until you see an Apple logo. (You may see a red slider prior to the Apple, that's OK, but just ignore it). When you see the Apple you can let go, and wait for it to restart itself.
CG