Small Business Server 2008 has several "Connect to the Internet" wizards under Getting Started Tasks in the SBS Console.  Depending on your order of setup, running the "Set up your Internet Address" task may activate DHCP without telling you it is doing so.  A key problem here is that, when activating it, a scope is auto-created which includes the entire subnet on which the SBS server sits.  The only exclusions auto-created might be the SBS address and that of the SBS’ gateway.  This could occur on a production subnet and cause IP-address conflicts with other live devices if not noticed quickly.