Zimbra Collaboration Suite (ZCS) 5.0 is a truly modern, innovative messaging and collaboration application. Zimbra is the leading open source solution for enterprise, service provider, education, and government environments; offering administrators and their end-users unmatched benefits. It's no wonder Zimbra is a popular choice for today's growing Mac and Linux email server base. Ajax based web collaboration is at the heart of ZCS 5.0. The powerful web client integrates email, contacts, shared calendar, VoIP, and online document authoring into a rich browser-based interface. Also, our unique open source Zimlet technology makes it easy for you to include custom 'mash-ups' in the ZCS web client. ZCS 5.0 also includes an elegant Ajax based Admin Interface plus full scripting tools to manage the ZCS server. Full support is provided for standards-based APIs (IMAP / POP / iCal / CalDAV) as well as MAPI and iSync, which enable seamless compatibility with other clients like Microsoft Outlook, Apple desktop suite, and Mozilla Thunderbird. Zimbra also offers Zimbra Mobile, which provides over-the-air "push" synchronization to smartphones as well as a Connector for BlackBerry Enterprise Server. The Zimbra solution also has a complete high security package including built-in anti-spam and anti-virus scanning. Now Zimbra also features Archiving and Discovery, an optional component to save and search email for various compliance issues.

O Uebimiau é um webmail universal, desenvolvido em PHP por Aldoir Ventura. è um software gratuito e pode ser instalado em qualquer servidor para a administração de emails.

- Pode ser instalado em qualquer plataforma;
- Não precisa de módulos em PHP extras
- Não necessita de banco de dados(como MySQL, PostgreSQL, etc) nem de IMAP;
- Compatível com POP3 e IMAP;
- Compatibilidade com o padrão MIME (permite enviar e receber e-mails HTML e texto);
- Não depende de cookies;
- Fácil instalação (Modificações em um único arquivo);
- Compatível com Apache, PHP, Sendmail ou QMAIL;
- Pode ser customizado em qualquer idioma (já está traduzido para 20 idiomas);
- Também pode ser customizado com o uso de skins

RoundCube Webmail is a browser-based multilingual IMAP client with an application-like user interface. It provides full functionality you expect from an e-mail client, including MIME support, address book, folder manipulation, message searching and spell checking. RoundCube Webmail is written in PHP and requires the MySQL database. The user interface is fully skinnable using XHTML and CSS 2.

Horde Groupware Webmail Edition is a free, enterprise ready, browser based communication suite. Users can read, send and organize email messages and manage and share calendars, contacts, tasks and notes with the standards compliant components from the Horde Project.
Horde Groupware Webmail Edition bundles the separately available applications IMP, Ingo, Kronolith, Turba, Nag and Mnemo.

HiveMail™ is a powerful web-based email program that allows you to offer personal email accounts to your site visitors. The powerful combination of the PHP scripting language and the scalable MySQL database makes HiveMail™ something your visitors will not pass over! Packed with many great features, HiveMail™ is the perfect solution to both professional and personal sites.

Innovating within the email server industry since 1998, Calacode develops @Mail, a robust integration of Open Source Technology, Unix, Strong Encryption, and industry-standard Groupware Features in a centralized messaging platform.

The Webmail software can be used as a Webmail interface to an existing mail server, a complete Email Server platform, or an Exchange mailserver replacement.

Seamlessly unifying messaging components, @Mail simplifies migration from outdated legacy systems. Filtering out the white noise of growing open-source options, @Mail is a reliable and complete messaging platform that includes full source code for complete control of your email server.

The optional @MailServer Appliance is a complete turn-key hardware solution with the @Mail Email Server software pre-loaded for rapid deployment and system reliability.

Features Include

- Complete WebMail Client
- Optional Email Server Backend
- Group Calendar / Scheduling
- MySQL Database Backend
- Anti Virus / Anti-Spam Scanning
- Web-based Administration (includes Branding, User Account Management, Security Settings, Mass Mailing, SMTP/POP3/IMAP4 daemon control, and much more)
- Wireless device (XHTML/WAP) WebMail Interface
- Mail Encryption via the Advanced WebMail Client Interface (up to 4096-bit)
- SMS Integration (allows users to receive notification of important messages)
- Spam Filter with Spamassassin Integration (configurable by both admin and user)
- Unrestricted Mailbox Quota Management
- Message Searching and Sorting
- Multiple Mailbox & Email Personalities
- Interface Available in 16 Languages
- Ajax WebMail interface
- Cross-Browser, Cross Platform Interfaces
- Migration and Import support for other mail systems
- Linux, Unix and Windows platform support
- Full source code provided for ease-of-customization and integration