Currently you can subscribe to Google Apps for free as long as it is in beta. Google says that all beta users will be able to keep it for free in the future, but at some point in time they will charge for it… So go there are get it now.
All you need is a domain and with this service you can host up to 50 email accounts with full gmail functionality, a calender, instant messaging and webpages for free. The catch: Well, it’s no surprise that Google shows Adwords ads everywhere 🙂
Google Apps for Your Domain lets you offer private-labeled email, instant messaging and calendar accounts to all of your users, so they can share ideas and work more effectively. These services are all unified by the start page, a unique, dynamic page where your users can preview their inboxes and calendars, browse content and links that you choose, search the web, and further customize the page to their liking. You can also design and publish web pages for your domain.
Organizations accepted by Google during the Google Apps for Your Domain beta period are eligible for free service for their approved beta users even beyond the end of the beta period, as described in the Terms of Service.