Setting up your Internet Address is the next very important task included in SBS 2008 Getting Started Tasks.
Based on the Public Domain name that you provide (Internet Address), the Wizard configures Remote Web Workspace, Microsoft Exchange and Sharepoint Services. It is important to note that you have to be careful, when choosing the name because changing it is not that easy. Though you can run the Wizard again, and specify a new name, you will not be able to change automatically the Sharepoint Services configuration. As a result, you will lose access to the internal web site in Remote Web Workspace.

If you are looking for the previous screencasts about the installation of Small Business Server 2008, and CIW (Connect to the Internet Wizard), you can find them here