[buug] Webmail App?

[Claude Rubinson]

Can anyone recommend a decent webmail app?  Needs to support POP3. I've
found some very basic ones, but I'm looking for something with a few more
features.  At a minimum, it needs an addressbook; folders would be nice
too.  Language is unimportant; server supports Perl, Python, PHP4, etc.  
Server has MySQL access.

Sites being hosted through a webhosting company, so I don't have root
access to the server.

Only other restriction is that the app must be free/open source software.

Thanks,

Claude