A friend of mine just got hired as an intern at my work. We needed someone and I knew he was looking. Everything worked out on both sides and he accepted.
Expectations for interns, at least in my experience:
1) You're going to get trained. There's a 99% chance you don't know what we want you to know
2) You're going to learn quickly, because otherwise you're gone in 3 months and that was worthless
3) You're going to be given a project (or piece thereof) that realistically can be finished or mostly finished by the time you leave.
So what I'm looking for in an intern (I did screening of applicants at my last job to replace myself as a co-op) is a willingness to learn, reasonably smart, and good time management. The latter 2 you can approximately screen for in GPA, or GPA + outside activities. If you're excited in whatever we do that will give you a big leg up, or if you've done something approximately similar to what that is.
My last job would also only seriously look for applicants in spring, though we did interviews year round. In summer we'd start hitting other companies' rejects that couldn't get a job for that summer. Fall was hit or miss, depending on if they wanted to start in spring or summer. Summer was more promising because it meant that the students thought ahead and were already looking for jobs.
That is, I knew her from active participation in a baseball fan forum (http://www.azsnakepit.com). She was cheerful, courteous, kind, etc. That is, she unconsciously demonstrated everything any sane businessperson would be looking for.
After Liz had a baby, she asked me for advice about how to find a part-time work-at-home job where she could learn a new skill (and avoid going stir-crazy from talking only to the baby). And I said, "Hey, _I_ need someone!" I'm now paying her a lot more money than she imagined, she's doing a great job, and the work is getting _done_.
Therefore, I recommend that you begin rooting for the Arizona Diamondbacks. Only good things can come of this.