Index: src/wp-includes/ms-functions.php
===================================================================
--- src/wp-includes/ms-functions.php	(revision 27391)
+++ src/wp-includes/ms-functions.php	(working copy)
@@ -1468,9 +1468,11 @@
 
 You can log in to the administrator account with the following information:
 Username: USERNAME
-Password: PASSWORD
+Temporary Password: PASSWORD
 Log in here: BLOG_URLwp-login.php
 
+Please change this temporary password when logging in for the first time. 
+
 We hope you enjoy your new site. Thanks!
 
 --The Team @ SITE_NAME' );
@@ -2118,13 +2120,15 @@
 		remove_filter( 'site_option_welcome_user_email', 'welcome_user_msg_filter' );
 		$text = __( 'Dear User,
 
-Your new account is set up.
+Your new account has been successfully set up: 
 
 You can log in with the following information:
 Username: USERNAME
-Password: PASSWORD
+Temporary Password: PASSWORD
 LOGINLINK
 
+Please change this temporary password when logging in for the first time.
+
 Thanks!
 
 --The Team @ SITE_NAME' );
Index: src/wp-includes/pluggable.php
===================================================================
--- src/wp-includes/pluggable.php	(revision 27391)
+++ src/wp-includes/pluggable.php	(working copy)
@@ -1299,7 +1299,8 @@
 		return;
 
 	$message  = sprintf(__('Username: %s'), $user->user_login) . "\r\n";
-	$message .= sprintf(__('Password: %s'), $plaintext_pass) . "\r\n";
+	$message .= sprintf(__('Temporary Password: %s'), $plaintext_pass) . "\r\n\r\n";
+	$message .= __( 'Please change this temporary password when logging in for the first time.' ) . "\r\n\r\n";
 	$message .= wp_login_url() . "\r\n";
 
 	wp_mail($user->user_email, sprintf(__('[%s] Your username and password'), $blogname), $message);