Does anyone know how to add a summary of average ratings (i.e. stars) onto the category view of the products?

I have the "Comments Plus +" review app on each of the product pages, but would like a summary of these on the category view so that customers don't have to click on each product to see the ratings. 

Here is an example page where I would like the star reviews: http://www.trogaguides.com/store/c6/Malaysia.html