Telltale Games has announced The Wolf Among Us for PlayStation Vita and iOS platforms for this Fall.
The game, which just came out on Xbox Live, PSN and PC, has yet to be given a definitive release date or pricing, but Telltale has stated that the pricing on iOS will be similar to The Walking Dead. It will also support iPad 2 and iPhone 4 and up, though I’m not sure why you’d want to play it on the iPhone’s relatively tiny screen.
Now, to answer the question as to whether or not you have to buy it again for Vita if you already bought in for PS3, the answer is: yes, it’s a completely separate purchase.
{Sources: Dtoid and PlayStation Blog}