When logged in as an Administrator user, click on the Account link at the top of the WebShuttle window, and then select Account Info from the menu that appears. This will take you to the Account Information page for your WebShuttle account.
The Account Information page has two main areas in different-colored boxes. The top box is gray, and displays the general information for the account. The bottom, white box displays information for each of the users associated with the account.
At the bottom of the top, gray box, there is a line that says "Current FTP Usage," along with the amount in MB and the number of files currently on the system.