To see what items you have showing up on expres try this link but at the end chage moodymama1024 to your name.
The shipping cost is determined based on your zip code. It shows up different for different customers. You get the same information as if you typed in your zip code to the shipping calculator, but it is done automatically. As for how the buyers will find it, the official release is either monday or Tuesday. I assume ebay will send out a notification of some sort when the official roll ot happens. You can find a lot of other info on this topic in the ebay sellers board founbd here