class Namespace_Module_Block_Onepage extends Mage_Checkout_Block_Onepage
{
    public function getSteps()
    {
        $steps = array();
        $stepCodes = $this->_getStepCodes();

        if ($this->isCustomerLoggedIn()) {
            $stepCodes = array_diff($stepCodes, array('login'));
        }

        foreach ($stepCodes as $step) {
            $steps[$step] = $this->getCheckout()->getStepData($step);
        }

        return $steps;
    }

    /**
     * Get active step
     *
     * @return string
     */
    public function getActiveStep()
    {
        return $this->isCustomerLoggedIn() ? 'billing' : 'login';
    }

    protected function _getStepCodes()
    {
        // Remove shipping from array
        return array('login', 'shipping', 'shipping_method', 'payment','billing');
    }

}

<global>
        <blocks>
            <checkout>
                <rewrite>
                    <onepage>Namespace_Module_Block_Onepage</onepage>
                </rewrite>
            </checkout>
        </blocks>
</global>