Google Apps is another superb service from Google. Google apps is basically a collection of several application and web storage. It includes: Gmail, Google Talk, and Google Calendar, Google Docs (text files, spreadsheets, and presentations), iGoogle, and Google Sites. So we can easily setup our mail box for our site and use this to send and receive mail using Google service. Suppose we have a domain "www.my_domain.com". Using google apps we can easily get mail account like "admin@my_domain.com, my_name@my_domain.com, whatever@my_domain.com" etc etc. Besides that mail holders can easily communicate among them using google talk, share their doc using google docs. Its very easy to setup the hole process and start the journey :) . Interesting thing is Google Apps has a free version i.e Standard Version, it supports 50 email address per domain. But the thing is to integrate this to our site, we must have full control of our site i.e we must have the administrative access to our site and domain control panel.