Besides spidey's concise and almost accurate response, there is another answer that I like to give people when they ask this question. They can ask the administration. Writing a letter isn't tough. Well, unless you attended U.S. public schools, then you might have trouble. Making the letter convey the information you want, in the language you need to use is much tougher. Make sure the letter is well worded, with polite, concise language written for the technical idiot (and don't use that phrase right there 😉).
The first topic you should explain is the benefits of pirated software, movies, and music to the average college student. Explain how the extra bandwidth being used by relentless porn addicts at 3p.m. is a good thing for the education of the students, despite the fact that none of the students can get to the educational resources the web has to offer, unless of course those sources deal with hair styling.
Next, explain how the, most likely, large ISP bill the college pays will not be affected by this change in policy. Money is, afterall, an important piece of the college experience. Why else would they charge you so much to drink, do drugs, and find as many GOOD friends?
And last, don't forget to mention the security benefits of such a policy change. Mention how Ashcroft wants college students to download the latest Legally Blonde movie. Explain how it makes everyone better consumers, and that may increase the sales in the various stores around campus. Mention Homeland Security, and how Bush doesn't want our freedoms limited by anyone but his administrators, and you may scare the powers that be into opening up the firewall. But focus less on these points and more on the fact that a large amount of the hacked systems out there used in DDoS attacks reside on college networks. I'm not sure how that point helps your cause, but try it anyways.
Good luck, and let us know how it turns out!
Ok, so this was quite sarcastic, but really, try writing a letter with some good information about how opening the firewall will help the school and you should be all set.