Timo Weingärtner has graciously offered to take over the maintenance of pam_pwdfile. Its development will henceforth be hosted at https://github.com/tiwe-de/libpam-pwdfile.
Old page contents follows
PAM, or pluggable authentication modules, is a very effective method by which applications can abstract the way that they authenticate and authorize users. Using PAM for example, a whole system can be switched from normal /etc/passwd to shadow passwords without recompiling a single binary, as was the case with older *ix systems. Linux being my OS of choice, I have had most contact with Linux-PAM, as maintained by Andrew Morgan. Please see the Linux PAM pages at http://www.us.kernel.org/pub/linux/libs/pam/.