You'll have to drop in the apache mod_auth_pam module which for some reason isn't included: http://pam.sourceforge.net/mod_auth_pam/ for web access - or if everyone has a local password you can just give apache read access to the /etc/shadow file.
Instead of giving read access to the shadow file, consider using mod_auth_external:
<http://www.unixpapa.com/mod_auth_external.html>
