WPML is a premium plugin from wpml.org which can add multi-currency and multi-lingual features to your site.
We're always creating lots of howtos on WooCommerce in general. We recently created a 6 part tutorial series on how to setup WooCommerce and WPML to be 100% multilingual and multicurrency. While this tutorial uses our Adrenalin theme the tutorial series can be used with any WooCommerce/WPML certified theme. Check out the 6 part WPML / WooCommerce setup tutorial.