First article I saw was at Anandtech above, and I'm sure other sites will cover it also.
Short take away points:
Same IPC as Skylake
Modified/updated process means more clock per power - unknown if this means it'll OC higher
Desktop parts not till 2017
If you're wondering if you should hold off on buying a Skylake desktop system, doesn't seem much in it apart from possibly higher clocks and/or a bit more power efficiency.
At least AMD will have a better idea what they're going against with Zen...