Per the Flexibits blog:
That's right, Fantastical now fits in your pocket! Since we released Fantastical for Mac, the most common question we've received is "where is the iPhone version?" A year and a half later, it's finally here.
I know I'm a hardcore nerd when practically the first thing I did on my phone this morning is hit the App Store to grab this. I played around with it briefly and it looks terrific. I love the Mac version; so good that it makes me want to use a calendar. It's already replaced the stock Calendar app on my first Home screen. All the nerds were/are raving about the app on Twitter, so I'm not alone in my adulation. Flexibits did a great job; fork over your $2 and get it.