bheadrick on "[Plugin: WooCommerce - excelling eCommerce] Woocommerce - Product variations on category/product list page with add-to-cart"

this will be available in 2.0, though it may require some theming.
basically, at the moment, there's no add to cart url for variations(meaning no way to add a variation to the cart outside of the single product page), but that's a feature they're adding into 2.0, which was just released to beta last week.