I believe all web access is free currently (someone correct me if that's wrong). The license says they're free to charge you if they want to (if people spend more time web surfing than buying books and htey get a big bill from Sprint for example). If they do this then rather than cut off web access entirely or require a premium monthly account charge or something I would expect they might limit it to certain web sites and chances are they'll always let you get to Wikipedia.
Amazon has a
lot of wiggle room here. They can start charging for data access, charging for access to sites other than some limited set, offer monthly data plans, offer subsidized services with ads or minimum monthly purchases from the store (this was my guess yesterday as to how they would pay for data access), offer premium service that includes two-way email, etc., etc.
But at this point the last thing they want to do is irritate their early adopters who are paying full-price for a new technology, so again I'm not overly worried. The license text is just there because they need to not lose their shirts if all people do is web-surf all day. An e-ink display doesn't make thr most dynamic web interface though
Z.