Create custom login page in wordpress, and hook in functions - http://www.paulund.co.uk/create-your-own-wordpress-login-page

functions.php

<?php
// Restrict dashboard access to administrator only
add_action( 'admin_init', 'ru_restrict_admin', 1 );
function ru_restrict_admin()
{
    if ( ! current_user_can( 'manage_options' ) && '/wp-admin/admin-ajax.php' != $_SERVER['PHP_SELF'] ) {
                wp_redirect( site_url() );
    }
}

// Hook failed login
add_action( 'wp_login_failed', 'ru_login_failed' );
function ru_login_failed($user)
{
    // check what page the login attempt is coming from
    $referrer = $_SERVER['HTTP_REFERER'];

    // check that were not on the default login page
    if ( !empty($referrer) && !strstr($referrer,'wp-login') && !strstr($referrer,'wp-admin') && $user!=null ) {
        // make sure we don't already have a failed login attempt
        if ( !strstr($referrer, '?login=failed' )) {
            // Redirect to the login page and append a querystring of login failed
            wp_redirect( $referrer . '?login=failed');
        } else {
            wp_redirect( $referrer );
        }

        exit;
    }
}

// Login Page Authentication
add_action( 'authenticate', 'ru_blank_login');
function ru_blank_login($user)
{
    // check what page the login attempt is coming from
    $referrer = $_SERVER['HTTP_REFERER'];

    $error = false;

    if($_POST['log'] == '' || $_POST['pwd'] == '')
    {
        $error = true;
    }

    // check that were not on the default login page
    if ( !empty($referrer) && !strstr($referrer,'wp-login') && !strstr($referrer,'wp-admin') && $error ) {

        // make sure we don't already have a failed login attempt
        if ( !strstr($referrer, '?login=failed') ) {
            // Redirect to the login page and append a querystring of login failed
            wp_redirect( $referrer . '?login=failed' );
        } else {
            wp_redirect( $referrer );
        }

    exit;

    }
}
?>

page-login.php

<?php
/**
 * Template Name: User Login
 */

$args = array( 'redirect' => site_url() );

if(isset($_GET['login']) && $_GET['login'] == 'failed')
{
	?>
		<div id="login-error" style="background-color: #FFEBE8;border:1px solid #C00;padding:5px;">
			<p>Login failed: You have entered an incorrect Username or password, please try again.</p>
		</div>
	<?php
}

wp_login_form( $args );
?>