According to Macrumors the OS X 10.6 Snow Leopard Build 10A432 got sent to developers. Rumor has it that the 10A432 build is the golden master for the release of Snow Leopard.
Apple already started the pre-order of the Snow Leopard Update a couple weeks ago. You can pre-order Snow Leopard on Amazon.com for $29.
The final release date of Apple OS X Snow Leopard has not been officially announced yet. Daring Fireball puts the release date already on August 28th.
More Snow Leopard News.