If you go to "My eBay" and select "Account" --> "Fees", it gives you an itemized list of all fees. If you sold something that had a separate shipping charge, it will separate the FVF for the item and the FVF for shipping on separate lines.
Of course, the FVF on shipping is the same as the FVF on the item. So if you know the FVF % for the category you're selling in, you can figure it out in your head. For example, if I sell a video game for $20 + $5 shipping, and I know that 10% is the FVF for that category, I know I paid $0.50 in FVF for the shipping alone.