Gmail is a free, advertising-supported email service provided by Google. Users may access Gmail as secure webmail, as well as via POP3 or IMAP4 protocols. Gmail was launched as an invitation-only beta release on April 1, 2004 and it became available to the general public on February 7, 2007, though still in beta status at that time. The service was upgraded from beta status on July 7, 2009, along with the rest of the Google Apps suite.

Web Email Enterprise - GMail Clone
☆☆ Deploy your own GMail Style Email Hosting Service in mins! Web Email Script Enterprise is the ultimate answer to your web users for easy, safe and reliable method of eliminating spam emails by offering disposable email address that expires after a certain time limit just like
AfterLogic WebMail Lite
AfterLogic WebMail Lite PHP provides open source webmail front-end for your existing mail server. The fast, clean and modern-looking AJAX user interface makes it easy to access mail and contacts. Users can check, preview, search, view, compose, send and otherwise process mail, use Inbox, Sent...
A complete messaging platform that provides Webmail, Calendaring, Groupware and Mobility across devices. Use your existing mail-server or the inbuilt SMTP/IMAP/POP3 stack provided by Atmail.
WebMail Pro
AfterLogic WebMail Pro is a browser-based e-mail front end, designed to work with your existing messaging solutions. From an administrator's perspective, the application is easy to install on your own server, easy to integrate and easy to maintain.
Gwebmail is an ajax powered webmail system with an interface similar to Gmail It is entirely written in PHP and uses MySQL to store messages It is modeled after the popular free email service from Google, gwebmail has a user friendly interface similar to Gmail but you will use this interface...
Corporate Email & Webmail Script - Gmail Clone
Inout Webmail - Open Source Email Portal Script Inout Scripts have been providing solutions to small business worldwide for nearly nine years. Inout Webmail has been one of the most successful webmail portal script, providing a feature rich environment with a user friendly interface with...