I'm looking for an open source application that will archive my email. It might do this by logging in to my POP3 account on a regular basis and copying the emails across, or it might just read my Unix mbox/maildir file/directory directly on the mail server.

It must be open and it must run on Linux (or any open OS actually). Ideally, it would have a web interface, but this is not a major requirement.

MXsense (http://www.mxsense.com/mxsense.html) seems to be pretty-much what I want, except it's not open.

I have no requirement for MS Exchange support.

Any suggestions?

The rationale (maybe a bit silly) is that I run Linux exclusively and it's still doesn't have an email client that is anywhere close to MS Outlook in terms of awesomeness, so I find myself switching between mail clients often. I would feel better about this if I had an archive of my emails, so it wouldn't matter which mail client I was using this month.