Apple unveils Mac OS X Snow Leopard, a powerful new version of the world’s most advanced operating system that includes hundreds of refinements, new core technologies, out of the box support for Microsoft Exchange and new accessibility features. Snow Leopard will ship as an upgrade for Mac OS X Leopard users in September 2009. Apple also unveiled a Developer Preview of Mac OS X Server Snow Leopard, a full 64-bit UNIX server operating system based on open standards that is up to twice as fast as its predecessor