I'm a student at a bush league school that doesn't have many connections to my field. Would it be in my interests to make a LinkedIn account for internship purposes?
But I agree with Nick Corcodilos, which is almost a tautology, he's by far the best author I've ever found on these subjects. One of the best things you can do for yourself in the long run is to read the appropriate stuff on his http://www.asktheheadhunter.com/ site, and you might want to sign up for his weekly newsletter, the July 23rd one was on this topic, and previous ones and/or items on the site have generally and specifically covered job boards.
His general specific advice for getting a job is not so relevant until you, say, get some of those internships or otherwise get the experience necessary to make a good case to an employer that you can do the job, but it's all worth reading. It's also very well written.
While you're at it, read his "Death by Lethal Reputation" essay and avoid what it talks about.
When someone in my personal network pings the hiring manager and asks if they can connect me with them, I'm already ahead of the rest. Even if the response is to send the application in through the regular channels, the hiring manager now knows to expect my application. And perhaps most importantly, they know that I have been already vetted for fit and sanity by a person in their personal network. I can refer to that link in the application cover, and help it stand out even further.
The in-system introductions at LinkedIn I consider worthless. Use those, and you get flagged as someone just clicking buttons.
Networking is crucial on any creative field. But if you're willing to artificially "enhance" your network, you're just devalueing that very network - and by extension, yourself. The only things that really matter are the personal connections. They are the ones that can help you - and the ones that you are willing to help yourself.
Yes, that would most likely be a good idea... most recruiters and HR people check LinkedIn these days.