Wow; here's a way to apply some "Google-fu" (like Kung-fu; get it?)
Okay, don't blame me for the bad pun. I got it from the first article I recommend you read: http://lifehacker.com/find-unadvertised-job-openings-with-a-clever-google-sea-1495871716. Here, you'll find out how to tap into one of the major ATS, applicant tracking systems.
Applicant tracking systems are beloved of company human resource departments because they offer a mechanized way to prune a list of many applicants to a much shorter, manageable list. They are also much loathed by job-searchers because unless you know how to game the system (using the right keywords) you're likely to be screened out even if you a great candidate.
And here is an article with a slightly more nuanced (but also more complicated) discussion of how to make mechanized systems work for you, rather than against you: http://www.glassdoor.com/blog/find-job-google-bing/.
Now... have you gotten your summer internship locked in yet for 2014??? If not, I'll bet you can use these tricks to rustle up some good prospects!