woocommerce/templates/checkout/form-checkout.php

<?php
/**
 * Checkout Form
 *
 * @author 		WooThemes
 * @package 	WooCommerce/Templates
 * @version     1.6.4
 */

if ( ! defined( 'ABSPATH' ) ) exit; // Exit if accessed directly

global $woocommerce; $woocommerce_checkout = $woocommerce->checkout();
?>

<?php $woocommerce->show_messages(); ?>

<?php do_action('woocommerce_before_checkout_form');

// If checkout registration is disabled and not logged in, the user cannot checkout
if (get_option('woocommerce_enable_signup_and_login_from_checkout')=="no" && get_option('woocommerce_enable_guest_checkout')=="no" && !is_user_logged_in()) :
	echo apply_filters('woocommerce_checkout_must_be_logged_in_message', __( 'You must be logged in to checkout.', 'woocommerce' ));
	return;
endif;

// filter hook for include new pages inside the payment method
$get_checkout_url = apply_filters( 'woocommerce_get_checkout_url', $woocommerce->cart->get_checkout_url() ); ?>

<form name="checkout" method="post" class="checkout" action="<?php echo esc_url( $get_checkout_url ); ?>">

	<?php if ( sizeof( $woocommerce_checkout->checkout_fields ) > 0 ) : ?>

		<?php do_action( 'woocommerce_checkout_before_customer_details'); ?>

		<div class="col2-set" id="customer_details">

			<div class="col-1">

				<?php do_action('woocommerce_checkout_billing'); ?>

			</div>

			<div class="col-2">

				<?php do_action('woocommerce_checkout_shipping'); ?>

			</div>

		</div>

		<?php do_action( 'woocommerce_checkout_after_customer_details'); ?>

		<h3 id="order_review_heading"><?php _e( 'Your order', 'woocommerce' ); ?></h3>

	<?php endif; ?>

	<?php do_action('woocommerce_checkout_order_review'); ?>

</form>

<?php do_action('woocommerce_after_checkout_form'); ?>