It's not an April Fool's joke -- the Onion really has released an iPad app, called The Onion Tablet. The company has had a few apps out already on the iPhone (and recently combined them into one), but this is the first time the hilarious fake news organization has appeared on the iPad. It's a pretty straightforward affair, allowing you to read and browse the latest and greatest from the humor newspaper of record, with a nice clean interface, and all of the content from the website available right there in iPad app form.
The only complaint so far seems to be the ads -- there's one right in your face when the app opens up that sticks around for what's said to be longer than it should. But that's not too big a deal, considering the app is completely free anyway. If you're a frequent Onion reader, it's probably one you'll want to pick up for your iPad or iPad 2.