This plugin allows you to use Unity Asset Server as a SCM.
Once this plugin is installed, you'll see Unity Asset Server as one of the options in the SCM. You configure the trigger as for any other SCM. In the plugin settings, you enter the database credentials for usage with your Asset Server database.
Notice that the plugin will not checkout anything, it is more like a very special build trigger for now. The Validate button allows you to test database connectivity with your settings. Configuration looks like this:
Version 1.1.1 (Sep 27, 2010)
Version 1.1.0 (Sep 23, 2010)