Perl/PHP webmail

[KMAN]

We're using a few servers running qmail+vpopmai+qmailadmin and of
course, sqwebmail. Although sqwebmail is one nice package, with lots of
complex stuff inside--we are looking for a recommendation for other cool
webmail that uses Perl or PHP.  Direct access to maildir is good, but
not necessary. We also prefer a package that interface nicely with
vpopmail's (simple--as Ken said : -) filtering mechanism.

Any suggestion is welcome.

-kman