RoundCube
From Hostek.com Wiki
What is RoundCube?
RoundCube is a web-based IMAP email client written in the PHP programming language.
RoundCube - Video Tutorials
How to manage your address book in RoundCube
How to save a draft message in RoundCube
How to create folders in RoundCube
Using multiple identities in RoundCube
How to mark messages in RoundCube
How to open an email message in RoundCube
How to edit your preferences in RoundCube
How to reply to or forward messages in RoundCube