When I figured out that Apple did not include the same clock app that is on the iPod Touch on the iPad, I was annoyed to no end! How stupid!
Do yourself a favor and go download the iHome/Sleep app AND the Nightstand app too. Both of these give you a way to have an alarm clock, dim the display and the sleep app gives you nice weather reports, social news feed updates from overnight and a way to play music to go to sleep with!
Both are free!