MacRumors has received word that a listing for the Mac Box Set version of OS X 10.6 Snow Leopard briefly appeared in Apple's online store earlier today. While the page, which listed the box set as shipping within 24 hours, is no longer available on Apple's site, an entry for it is retrieved in Google searches for the product number, MC209Z/A.

The Mac Box Set bundles Mac OS X with iLife '09 and iWork '09. A Leopard version was launched in late January at a price of $169, and a similar version will be available for Snow Leopard at the same price point. Apple has noted that the box set will be required for users looking to upgrade from OS X 10.4 Tiger to Snow Leopard, as the standalone OS X Snow Leopard, priced at $29, will require an existing installation of OS X 10.5 Leopard.
The brief appearance of the Snow Leopard Mac Box Set provides further evidence that the launch of Apple's new operating system is rapidly approaching. Snow Leopard Build 10A432 was reportedly designated the "Golden Master" version to be sent to manufacturing for the public release, and several sources have also claimed that Apple may be releasing Snow Leopard as early as Friday, August 28th, ahead of Apple's previously-announced September launch window. Over the weekend, purported photos of the Snow Leopard packaging also surfaced, indicating that manufacturing has indeed begun.
Update: MacRumors has now received a screenshot of the page: