Google is currently offering schools a free hosted solution for their email, calendar, and chat through Google Apps for Education.
The core Google Apps for Education suite includes:
Gmail: Email storage and search tools that help your students find information fast and instant messaging from right inside their accounts.
Google Calendar: Users can organize their appointments and share events and calendars with others.
Google Docs: Share documents, spreadsheets, and presentations. Collaborate in real-time with your team or with your whole organization.
Google Groups: Users and website owners can create and manage collaborative groups. Users can have email discussions and share documents, calendars, sites and folders with the members of a group. They also have the ability to view and search group discussion archives.
Google Talk: Users can call or send instant messages to their contacts for free anytime, anywhere in the world.
Google Sites: Work together to keep related documents, web content and other information in one place, on one site.
Google Video for Education: A video hosting and sharing solution that enables organizations to use video as an effective medium for internal communication and collaboration.