Free Web Mail PHP Scripts (Email Clients POP3/IMAP/Webmail Scripts)

Roundcube - Open Source Webmail Software

Roundcube can be installed on your website to give you access to your email via IMAP. It supports MIME messages (including attachments), HTML email, message forwarding, address book with "find-as-you-type" facilities and groups and LDAP-connectors, searching of email and contacts,
threaded message listing, access control lists, unlimited users, multiple sender identities, IDNA support, etc. You will need PHP as well as access to database facilities (either MySQL, PostgreSQL, MSSQL, or even just SQLite). The software is open source and licensed under the GNU General Public License. 

IMP Webmail Client - The Horde Project

 

IMP provides webmail access to IMAP and POP3 email accounts. It requires PHP and the open source Horde Framework. It supports attachments, spell checking, address books, multiple folders and multiple language support. 

V-webmail - PHP based webmail application

 

V-webmail is a PHP webmail client that supports IMAP and POP3 mailboxes (including support for SSL connections), MIME attachments, address books, drag and drop message moving, message folders, multiple identities / personalities, a search facility, HTML mail, filtering, virtual hosting (that is, one installation can be used to support multiple domains), the ability to use MySQL, PostgreSQL or plain files to store preferences, security features like disabling of HTML mail, certain tags (eg script or object), external images, etc. The system is template based, and you can easily change to look-and-feel of the product by modifying the templates used. 

NOCC Webmail Client

 

The NOCC web mail client, written in PHP, allows you to run a web interface to your POP3 or IMAP mailbox and send mail from the web via sendmail or SMTP. It supports MIME attachments, supports a number of languages, is themable, renders pages in XHTML and works with text browsers, does not require frames or cookies, etc. This PHP email client works on Win32 (Windows) and various Unix systems. It is distributed under the GNU General Public License. 

SquirrelMail

 

SquirrelMail is a fairly well-known PHP4 script that allows you to check your mail via IMAP, and send via SMTP. It has MIME support (attachments, HTML mail, etc), address books, folders, and renders in HTML 4 with no JavaScript (making it compatible with more browsers). It is released under the GNU General Public License. 

Popper

Popper supports attachments, HTML email, replying, forwarding, composing, address books, SPAM blocker, calendar, etc. It generates HTML code that can be viewed even with text-based browsers like Lynx. It allows you to check multiple POP3 email mailboxes.

kmMail

 

kmMail is a MIME compliant email script that allows you to send, check, reply, forward, compose email, handle attachments, etc, via your browser. It supports IMAP and POP3.