Index: wp-includes/general-template.php
===================================================================
--- wp-includes/general-template.php	(revision 23585)
+++ wp-includes/general-template.php	(working copy)
@@ -199,12 +199,12 @@
 /**
  * Returns the Log Out URL.
  *
- * Returns the URL that allows the user to log out of the site
+ * Returns the URL that allows the user to log out of the site.
  *
  * @since 2.7.0
- * @uses wp_nonce_url() To protect against CSRF
- * @uses site_url() To generate the log in URL
- * @uses apply_filters() calls 'logout_url' hook on final logout url
+ * @uses wp_nonce_url() To protect against CSRF.
+ * @uses site_url() To generate the log out URL.
+ * @uses apply_filters() calls 'logout_url' hook on final logout URL.
  *
  * @param string $redirect Path to redirect to on logout.
  * @return string A log out URL.
@@ -224,11 +224,11 @@
 /**
  * Returns the Log In URL.
  *
- * Returns the URL that allows the user to log in to the site
+ * Returns the URL that allows the user to log in to the site.
  *
  * @since 2.7.0
- * @uses site_url() To generate the log in URL
- * @uses apply_filters() calls 'login_url' hook on final login url
+ * @uses site_url() To generate the log in URL.
+ * @uses apply_filters() calls 'login_url' hook on final login URL.
  *
  * @param string $redirect Path to redirect to on login.
  * @param bool $force_reauth Whether to force reauthorization, even if a cookie is present. Default is false.
@@ -247,6 +247,21 @@
 }
 
 /**
+ * Returns the user registration URL.
+ *
+ * Returns the URL that allows the user to register on the site.
+ *
+ * @since 3.6.0
+ * @uses site_url() To generate the registration URL.
+ * @uses apply_filters() calls 'register_url' hook on final URL.
+ *
+ * @return string
+ */
+function wp_registration_url() {
+	return apply_filters( 'register_url', site_url( 'wp-login.php?action=register', 'login' ) );
+}
+
+/**
  * Provides a simple login form for use anywhere within WordPress. By default, it echoes
  * the HTML immediately. Pass array('echo'=>false) to return the string instead.
  *
@@ -338,7 +353,7 @@
 
 	if ( ! is_user_logged_in() ) {
 		if ( get_option('users_can_register') )
-			$link = $before . '<a href="' . site_url('wp-login.php?action=register', 'login') . '">' . __('Register') . '</a>' . $after;
+			$link = $before . '<a href="' . esc_url( wp_registration_url() ) . '">' . __('Register') . '</a>' . $after;
 		else
 			$link = '';
 	} else {
Index: wp-login.php
===================================================================
--- wp-login.php	(revision 23585)
+++ wp-login.php	(working copy)
@@ -451,7 +451,7 @@
 <p id="nav">
 <a href="<?php echo esc_url( wp_login_url() ); ?>"><?php _e('Log in') ?></a>
 <?php if ( get_option( 'users_can_register' ) ) : ?>
- | <?php echo apply_filters( 'register', sprintf( '<a href="%s">%s</a>', esc_url( site_url( 'wp-login.php?action=register', 'login' ) ), __( 'Register' ) ) ); ?>
+ | <?php echo apply_filters( 'register', sprintf( '<a href="%s">%s</a>', esc_url( wp_registration_url() ), __( 'Register' ) ) ); ?>
 <?php endif; ?>
 </p>
 
@@ -510,7 +510,7 @@
 <p id="nav">
 <a href="<?php echo esc_url( wp_login_url() ); ?>"><?php _e( 'Log in' ); ?></a>
 <?php if ( get_option( 'users_can_register' ) ) : ?>
- | <?php echo apply_filters( 'register', sprintf( '<a href="%s">%s</a>', esc_url( site_url( 'wp-login.php?action=register', 'login' ) ), __( 'Register' ) ) ); ?>
+ | <?php echo apply_filters( 'register', sprintf( '<a href="%s">%s</a>', esc_url( wp_registration_url() ), __( 'Register' ) ) ); ?>
 <?php endif; ?>
 </p>
 
@@ -703,7 +703,7 @@
 <p id="nav">
 <?php if ( ! isset( $_GET['checkemail'] ) || ! in_array( $_GET['checkemail'], array( 'confirm', 'newpass' ) ) ) : ?>
 	<?php if ( get_option( 'users_can_register' ) ) : ?>
-		<?php echo apply_filters( 'register', sprintf( '<a href="%s">%s</a>', esc_url( site_url( 'wp-login.php?action=register', 'login' ) ), __( 'Register' ) ) ); ?> |
+		<?php echo apply_filters( 'register', sprintf( '<a href="%s">%s</a>', esc_url( wp_registration_url() ), __( 'Register' ) ) ); ?> |
 	<?php endif; ?>
 	<a href="<?php echo esc_url( wp_lostpassword_url() ); ?>" title="<?php esc_attr_e( 'Password Lost and Found' ); ?>"><?php _e( 'Lost your password?' ); ?></a>
 <?php endif; ?>