The term Google Apps generally refers to the suite of Google services (Gmail, Docs, Sites, etc) that a person or organization uses under their own registered domain. For example, I have a Google Apps account for Free Technology for Teachers through which I access Gmail, Google Sites, Docs, Voice, Alerts, and other Google services. This is slightly different than a standard Google account because all of my services are linked together under the banner of Free Technology for Teachers which is why my email is richardbyrne (at) freetech4teachers (dot) com even though it's powered by Gmail.
There are four different versions of Google Apps. Here's how Google explains them on their official blog.
- Google Apps is our free service geared towards families, entrepreneurs and other groups up to 50 users.
- Google Apps for Business offers 25GB of email storage per user, a 99.9% uptime guarantee, data migration capabilities, advanced management tools, telephone support, added security features and more, all for $50 per user per year.
- Google Apps for Government is FISMA certified and designed with local, state and federal agencies in mind.
- Google Apps for Education offers many benefits of Google Apps for Business, but at no cost to schools, universities and qualifying non-profits.