Excerpt from the post on the SBS blog by group program manager Dean Paron:

On behalf of the SBS team, I am extremely pleased to announce that Windows Small Business Server 2008 software has been finalized!  Today both SBS Standard and Premium are being released to manufacturing, which means we begin the process of finalizing international versions, creating media, building packaging, delivering the product to distribution channels and handing it off to our OEM partners, so it will be widely available by our November 12 launch.  (More information about launch will come in the future.) 
 
Joel Sider