Rovio has released a gameplay trailer for Angry Birds Epic, the battle-based role-playing game for iPhone, iPad and iPod touch that is now available in Australia and Canada. The game will be free with in-app purchases but is not expected to launch in the UK or US until a later date, after the bugs found during its "soft launch" are presumably ironed out.
When it is released on a more global basis, the game will also be available for Android and Windows Phone 8, but if you want to play it now, you'll need to have an iOS device and either an Australian or Canadian iTunes account.
Angry Birds Epic has RPG elements, and the dedicated Rovio site has details on a couple of the characters - a knight and a mage, based on Red and Chuck birds. The baddies that must be defeated through turn-based battles are, of course, the pigs. The game is set, after all, on Piggy Island.