Well it shows the options in the cart...but not the checkout, as it would take up a lot of room if you have multiple options. I haven't tried it, but you could try adding this code to that line:
Code:
{if $products[product].product_options ne ""}
{$lng.lbl_selected_options}:
{include file="modules/Product_Options/display_options.tpl" options=$products[product].product_options}
{/if}