Is anything else connecting to the internet wirelessly (Iphone, laptop, computer, etc) If they won't, it means something is wrong with either your router or your internet provider (Mine provider drops connection about once a month at the moment)
If it's your router, try (And i can't believe I'm actually saying these words) switching it off then on. (Leave about 30 seconds before switching it back on) It works on router problems 90% of the time.
If it's your provider, it's a waiting game until they get things working again. Might be worth giving them a call to find out what's going on, they may not even be aware of a problem.
But... If it's none of those, and your other stuff can connect just fine, try resetting your iPad network settings Settings > General, then tap Reset > Reset Network Settings.
If you still have nothing, put in a call to Apple support. You should have a free 90 day support line. (Check the docs that came with it)
Boy am I embarrassed.....
I went through everything I could on the iPad.
I checked my Xbox to see if it was connecting to the internet, and it was.
I was all set to place a call to Apple and shell out the $29 for a call when I sudddenly realzied my Xbox is hardwired to my internet.
So I checked my Airport Express and it was sending a great signal.....but the wire connecting it to my router had come loose.
Plugged it back in and viola!
Don't be embarrassed, we all do things like that. I remember calling out an engineer once to fix a problem with a printer. After some consideration, his opinion was that 'it would help in future if I switched it on at the mains socket'!
Following that, I've never been embarrassed by anything - except my children, of course, but that's another matter entirely.