I am trying to develop a shipping module. I am not as familiar with the inner workings of zen cart as I would like to be. The goal of the shipping module is to apply a custom shipping cost for two day delivery according to product and product attributes. I think I have figured out a process but I don't know exactly how to get some of the data that I need to perform it.

how would I retrieve the product id's from all the products in the shoping cart?
How would I find out if the products in the cart have attributes assigned to them?

I know these may seem like nub questions but... well I kind of am.