Good experience with Shipbikes.com
I recently shipped two bikes from NYC to Tampa using Shipbikes.com. Online, that company sold me FedEx shipping labels appropriate for the size and weight of the two bike boxes that I packed. I attached the labels and took the boxes to a FedEx location; they arrived in Tampa four days later. The cost of the two labels was around $150, a bit over half of the cost had I bought the labels directly from FedEx. I have no connection to Shipbikes.com.