Currently, the product listing page doesnt support passing product id or sku in the querystring but the product listing page does support passing the categoryid in the querystring. For example:
http://www.airsoftguns360.com/Home/tabid/38/Default.aspx?categoryid=1
When the category id is passed in the querystring the products will be filtered by category. So you could add all the products you want to filter on the product listing page to a category and pass the categoryid in the querystring.
Also, just an fyi the cart page supports passing productid and sku in the querystring if you want to add products to the cart using the querystring. All the querystring variables supported in the cart are documented on page 242 of the cart users guide here
http://www.smith-consulting.com/Porta...
thanks,