Apple has made documentation available for 10.6, which is available here..
http://www.apple.com/server/macosx/resources/documentation.html
At first glance, it appears to be a vast improvement from the documentation of 10.0-5, going into the detail of the different relationships between applications, as well as breaking out several applications that used to be grouped together.
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Documentation refers to the command-line tool /System/Library/ServerSetup/serversetup which has been removed in Snow Leopard Server…