Apple has seeded a new version of Snow Leopard (Build 10A190) to developers this morning. Last night they had emailed ADC members that a preview build of Snow Leopard was made available to them, but the download links were not live until this morning. Snow Leopard is the codename for the next major revision of Mac OS X. Apple has said that they would be focusing on quality and performance in Snow Leopard. In particular, Apple has made it clear that there will be efforts to improve support for multi-core processors and GPU processing.
Source:→ Mac Rumors