Sony has announced a partnership with Unity that'll let the popular dev tools work with their platforms, including PS4.
I can't warn indie developers away from Unity enough. We spent thousands of dollars to be able to develop and self-publish on iOS and Android, only to have them silently remove features we were using with nearly every release. Because the licenses are non-transferrable, I literally can't even give Unity away. We switched to MonoTouch + MonoGame, and it's been absolutely awesome. Their developer support is amazing, regardless of your size. Additionally, it's easy to build the same code in the PlayStation Mobile SDK! If that's not enough, it's literally 1/10th the cost of Unity. I love the concept of Unity, but the reality just isn't there for self-publishing indies on tight budgets.