[Plugin:WP-eCommerce] Show Current Brand on Single Product Page

Does anyone know the php code/function in WP-eCommerce to determine the current category id? For example, if I have the following Brands category group:

Brands
– Adidas
– Nike
– Reebok

and if I click on Nike, I am taken to the product page which shows all Nike branded products. Is there a function or variable that will tell me what the current group/sub-group (in this case Nike) is? This seems like something basic.