The free FAN version includes a basic timer and the uploader, most likely to be used by spectators or for personal timing situations, while the $75 iPhone / $150 iPad Webscorer PRO in-app upgrade from FAN includes a sophisticated timing program, designed to handle just about any type of race (or practice), from races with interval starts to wave starts to relays, likely to be used by coaches or race officials.
Via ReadWriteWeb.com, see also FAN and PRO demo videos.