Select a product from the refular product list. On the top of the screen under the "More" button, there should be an option "View stock per location" or something similair.

Samba, read the get_product_available method from stock/product.py, it gives you the overview of how to get the quantity of a certain product with various criteria.  Specifically for location, you put in {'location': XXX} into the context when you browse or read the product, then you get the qty_available or virtual_available of the read/browse result.