Google Sites blog notifies that now Google Apps domain administrators can map public sites hosted on Google Sites to their own domains. Sites can be mapped individually to a specific URL, like http://www.example.com, and as a group under a specific URL, like http://sites.example.com/[name of site].
Map a site to a specific URL: The standard URL of a site in Google Apps currently looks like http://sites.google.com/a/example.com/site-name, but now you can let users access your site at a URL on your domain that is easier to remember. The new location can be your domain home page or any sub-domain in your domain (e.g. http://www.example.com, http://info.example.com, http://wiki.example.com, etc.), and can be set up on the “Web Addresses” tab of the Sites service settings in your Google Apps control panel.
Change the root URL for all sites: If you have several sites, you can also make them automatically accessible at a designated URL on your domain. For example, instead of being at http://sites.google.com/a/example.com/site-name, the administrator can make them available at http://sites.example.com/site-name or at any other sub-domain.
Remember these new features are currently only available for public sites in Google Apps (mapped URLs to private sites will redirect to the standard URL). You can find more details in the help center, which notes that private sites are redirected to the standard URLs. For more details on this topic and specific setup instructions.
“A wiki is a website designed for collaboration. Unlike a traditional website where pages can only be read, in a wiki everyone can edit, update and append pages with new information and without knowing HTML. Wikis are great for all types of collaboration, from writing documents and managing projects to creating intranets or extranets,” explained JotSpot's intro tour.