One of my clients is looking for a webmail solution to install on a RaQ. The RaQ is not handling the e-mail (yes, could be easy if it does, but it doesn't...) and the other server is POP3.
www.squirrelmail.org
Although I agree Squirrelmail is a good package it is primarily designed for use with a local IMAP server - from his request it sounds like he wanted to connect to a remote (on another server) POP3 mailbox.
But... there are various POP3 add-ons available for Squirrelmail that allow it to collect mail from another server - the problem is these are not standard / build-in etc.
Thanks...