Don't make the postgres user in the Users control panel. Just copy the www user from within NetInfo? manager. Also, you should create a postgres group for this user, and put it in that group.

It's nice to have it boot up to Postgres. You put the startup items into /Library/StartupItems?.

%mkdir POSTGRES
%cd POSTGRES
%cat > POSTGRES
#!/bin/sh
. /etc/rc.common
echo "Postgres : " ${POSTGRES}
if [ "${POSTGRES}" = "-YES-" ]; then
ConsoleMessage? "Starting Postgres Database Server"
/usr/local/pgsql/bin/postmaster -D /usr/local/pgsql/data > /var/log/postgres 2>&1 &
fi
%cat > StartupParameters?.plist
{
Description = "postgres database server";
Provides = ("POSTGRES");
OrderPreference? = "None";
Messages =
{
start = "Starting postgres server";
stop = "Stopping postgres server";
};
}

That's it, pretty much. Delete leading spaces. If it's too cryptic, maybe you should not be running postgres quite yet.