For versions other than Deluxe can still purchase this great feature at :
http://www.vpasp.com/virtprog/modules.htm
This One Page Checkout allows your customer to sign in, enter their billing/shipping information, view available shipping options, select available payments, view any tax/discount/shipping cost and total amount, also allow to enter any coupon/gift card at just one single form.
This feature simplify the checkout process page-by-page to one single form to checkout.
It will reduce shopping cart abandonment by offering a streamlined approach to the checkout process.
Your customers can also checkout as guest without need to register using this One Page Checkout.
To enable this great feature, you need to change the following Software Configuration options.