password function for PostgreSQL

Looking for a postgresql function similar to the password function in
MySQL.  In MySQL putting  --password($password)-- in an insert query
encrypts the value of $password that is stored in the table.  You can
use password($password) to compare a password entered by a user in a
later query with the stored value of $password.

This is not a password for a user registered in pg_shadow, rather it
is to limit someone going in through a public web interface to only
those records in a table that are associated with a certain login and
password combination.

The web interface is written with PHP so I may have to simply encrypt
the password with a PHP function before storing or comparing it.

Tom
Tom Hodges, hodges@xprt.net or tom_hodges@yahoo.com
ICQ 10149621, YahooMessenger tom_hodges
Mail: 14314 SW Allen Blvd, #317; Beaverton OR 97005 USA