SquirrelMail : SquirrelMail is a standards-based webmail package written in PHP. It includes built-in pure PHP support for the IMAP and SMTP protocols, and all pages...
PeoplePods : PeoplePods is a developer-friendly social software toolkit
Build applications where people meet, talk, share, read, work, publish and explore.
WikkaWiki : WikkaWiki is a flexible, standards-compliant and lightweight wiki engine written in PHP, which uses MySQL to store pages.