"Hey Siri" support and possibly wireless charging case alongside AirPower charging mat.
Mac OS X 'Snow Leopard' to Focus on Performance, Quality
We have delivered more than a thousand new features to OS X in just seven years and Snow Leopard lays the foundation for thousands more, said Bertrand Serlet, Apples senior vice president of Software Engineering. In our continued effort to deliver the best user experience, we hit the pause button on new features to focus on perfecting the worlds most advanced operating system.
A new technology called "Grand Central" will make it easy for developers to create programs that take full advantage of the power of multi-core Macs. Also introduced is Open Compute Library (OpenCL), which extends the computing power of the GPU to any application written with OpenCL commands. Snow Leopard will also raise the software limit for RAM to 16 TB.
Beyond speed enhancements, Snow Leopard will also include out-of-the-box support for Microsoft Exchange 2007. Apple is aiming for the software to ship in "about a year."
Other announcements made at WWDC include 3G iPhone, 2.0 Firmware, SDK, MobileMe.
Update: Apple posted a Snow Leopard page on their website.