According to iLounge
So the adapters will work with stereo docks, but not video docks or some car docks. I doubt most of us are using iPod-out, since I never heard of it before, and it's not the same as regular audio-out. I think. We'll see.
Apple has confirmed that its Lightning to 30-Pin Adapters will be capable of passing iPhone 5 audio to prior Dock Connector-based docks, speakers, and cables, but will not support video out from the iPhone 5 to older video accessories, or “iPod out” mode transmission of data and album art, used in some car and home video dock accessories.
At least I'll have a good excuse to buy an HDMI adapter instead of using my old 30-pin component adapter, whenever it comes out. Although my wife is now pushing for an Apple TV...