PC Magazine reports: "'Google Sites is a new collaboration tool that allows anybody with Google Apps to create sites with just one click,' Scott Johnston, product manager for Google Sites, said in a video demonstration. 'Your content is instantly searchable using Google search technology and you have full control over who can access your information. You can use this no matter what size your organization.'"
I am sorry to say but Google Sites has a long way to to be any real threat to SharePoint. SharePoint is a great application if its implemented correctly.