Source From: http://us.battle.net/d3/en/forum/topic/5912162971?page=8#141

We have no plans to release PvP as paid DLC. As stated previously, our goal is to release PvP with the 1.1.0 content patch (which, as with all of our patches, will be available for free to all Diablo III players). While we don't have a date to share at this time for when 1.1.0 will released, we'll be providing more information as the development process continues. Thanks!