Clarify PGPASSWORD usage:

! authentication.  Use of this environment variable is not
! recommended for security reasons (some operating systems
! allow non-root users to see process environment variables via
! <application>ps</>); instead consider using  the
! <filename>~/.pgpass</> file (see <xref linkend="libpq-pgpass">).

doc/src/sgml/libpq.sgml

 <!--
-$PostgreSQL: pgsql/doc/src/sgml/libpq.sgml,v 1.179 2005/02/26 14:21:40 momjian Exp $
+$PostgreSQL: pgsql/doc/src/sgml/libpq.sgml,v 1.180 2005/02/26 18:39:04 momjian Exp $
 -->
 
  <chapter id="libpq">
@@ -3691,9 +3691,11 @@ sets the user name used to connect to the database.
 </indexterm>
 <envar>PGPASSWORD</envar>
 sets the password used if the server demands password
-authentication.  This environment variable is not recommended for security
-reasons; instead consider using the <filename>~/.pgpass</>
-file (see <xref linkend="libpq-pgpass">).
+authentication.  Use of this environment variable is not 
+recommended for security reasons (some operating systems
+allow non-root users to see process environment variables via
+<application>ps</>); instead consider using  the 
+<filename>~/.pgpass</> file (see <xref linkend="libpq-pgpass">).
 </para>
 </listitem>
 <listitem>