Wikipedia
Uebimiau
UebiMiau is a webmail reader application supporting both IMAP and POP3 protocols. It can be installed without dependence of any PHP's extra modules or a separate database. It is Open source software published under GNU General Public License (GPL).
UebiMiau has not been developed since March 2006 and does not work with PHP 5.3 due to its use of deprecated functions. A new project, which is a forked reboot of UebiMiau based on the jimjag patches, named Telaen is an actively developed drop-in replacement.