http://www.thinkfree.com/
Thinkfree is similar to Zoho. It's a hosted, online office suite. It's also available in self installed versions. No email capability (that I can see).
http://www.google.com/a/help/intl/en/index.html
Google Apps is the hosted mail / docs / etc product from Google. It comes in Free or Premier ($50/year/user).
http://zoho.com/
Zoho is an online office suite, similar to Google Apps. It includes a hosted mail product.