A free vQmod that removes step 3 (delivery details) on the checkout page, adapted to work with Sellegance theme.

<modification>
<id>Step 3 Checkout (Sellegance, Clearshop OpenCart 1.5.6.x)</id>
<version>1.3</version>
<vqmver>1.0.8</vqmver>
<author>ffct.cc</author>
<file name="catalog/view/theme/*/template/checkout/checkout.tpl">
<operation>
<search position="replace"><![CDATA[
<section id="shipping-address"
]]></search>
<add><![CDATA[
<section id="shipping-address" style="display: none"
]]></add>
</operation>
<operation>
<search position="replace"><![CDATA[
$('#shipping-address .checkout-content').slideDown('slow');
]]></search>
<add><![CDATA[
$("#shipping-existing select").prop("selectedIndex", $("#payment-existing select").prop("selectedIndex"));
$('#shipping-address #button-address').click();
$('#button-shipping-address').click();
]]></add>
</operation>
</file>
<file name="catalog/view/theme/*/template/checkout/guest.tpl">
<operation>
<search position="replace"><![CDATA[
<label for="shipping">
]]></search>
<add><![CDATA[
<label for="shipping" style="display: none">
]]></add>
</operation>
</file>
<file name="catalog/view/theme/*/template/checkout/register.tpl">
<operation>
<search position="replace"><![CDATA[
<label for="shipping" class="label-group">
]]></search>
<add><![CDATA[
<label for="shipping" class="label-group" style="display: none">
]]></add>
</operation>
</file>
</modification>

Original: http://forum.opencart.com/viewtopic.php?f=131&t=49258