Today Google released Google Apps for Your Domain or Google Hosted Communications Services, which is targeted at sysadmins who want to provide Google tools to their company.
Google —”Now you can offer private-labeled email /Gmail, IM (Google Talk), Google Calendar tools, and Google Page Creator to all of your users for free, so they can share ideas and get things done more effectively. You can design and publish your organization's website, too. It's all hosted by Google, so there's no hardware or software for you to install or maintain.”
To utilise this service, you must have a previously approved account with Google Domian or apply for a new account.