OS X: Snow Leopard is coming (10.6)
On the heels of OS X 10.5.3 Apple has already started seeding the next version of OS X to developers:
When released, Snow Leopard will include out-of-the-box support for Microsoft Exchange 2007 built into Mail, Address Book, and iCal.
Snow Leopard will also provide full 64-bit technology to support up to 16TB of RAM (500 times more than what is possible today). The support of multicore systems (themed “Grand Central”) will introduce enhancements to make all of OS X multicore aware and optimizing it for allocating tasks across multiple cores and processors.
Snow Leopard will also introduce a streamlined, next-gen multimedia platform — QuickTime X — which will feature optimized support for modern codecs and more efficient media playback, making it ideal for any application that needs to play media content.