Universal Express works much like Fastpass. (In fact, it was created shortly thereafter in response to Disney's Fastpass.) It IS free for all guests to use like at Disney.
What you might be confusing this with is the "Express" service that Universal resort guests get. As a guest at one of their resorts, your room key serves as an access pass to all express lines all day long. There is also another option where you can actually purchase a book of express passes when you enter the park. Don't be trapped into this though. You do NOT need to purchase the Express pass booklet in order to get the express pass privledge. It may seem like that when you enter the gates as there are employees encouraging you to buy them with little explanation (especially for the niave guest). Express pass service is FREE to all guests and works much like FP (one express pass per attraction for a specific time). The major benefit of the booklet is that it automatically gives you all the express passes that you can use (one per attraction) that can be used at any time of the day. The booklet might be good if the parks are REALLY busy, but aren't necessary to get everything done.
