I've embedded the ustream below. Please note a few things. First, as I indicated above, the first seven minutes are small talk (although interesting as well, I think); the formal question and answer portion starts at about the seven minute mark.
Second, the audio quality starts decreasing about halfway through. Not sure if that was a Skype issue, or bandwidth issues on his end or ours, but you'll have to concentrate more as it goes on to understand his end.
Third, you'll notice there are three students asking the questions. This was actually a group of four students, but the fourth student was in a final exam so couldn't be present for this part. Due to scheduling conflicts, this was the best time we could come up with, so the students asking the questions, as well as about twenty-five other students in the audience, were all there in between their scheduled final exams.
Finally, this was part of an assignment where students are reading books that are sometimes controversial and then making a case for why the book should be approved or not by a school board. This particular group was presenting during the final exam period that was directly after this Skype call with Cory Doctorow. They purposely made their first formal question to him be why he though the book should be read by ninth graders so that, less than forty minutes later, they could pull up the archived ustream and easily play his answer (since it was at the beginning - well, after the small talk) as part of their presentation (which they did). Very. Nice.