It is the same approach, which you have already used for your mobile sites. You just need to create a mobile page with some repeater, which will display products and its transformation will contain the shopping cart control like this:
<%@ Register Src="~/CMSModules/Ecommerce/Controls/ProductOptions/ShoppingCartItemSelector.ascx" TagName="CartItemSelector" TagPrefix="uc1" %>
<uc1:CartItemSelector id="cartItemSelector" runat="server" ShoppingCartUrl="~/Mobile/Special-pages/Shopping-cart.aspx" SKUID='<%# ValidationHelper.GetInteger(Eval("SKUID"), 0) %>' SKUEnabled='<%# ValidationHelper.GetBoolean(Eval("SKUEnabled"), false) %> ' AddToCartImageButton="addtocart.gif" AddToCartLinkText="Add to shopping cart" ShowProductOptions="true" ShowUnitsTextBox="true"/>
And as you can see in the control above, you need to also create some shopping cart page, into which you place the Shopping cart
webpart, which will be able to handle the check-out process.