An internship is a good way to get you out of a tough spot in your career. Often people look at internships as simply unpaid labor, but in fact, they are a great way to get a foot in the door in an industry that would otherwise be out of reach to you.

If you 're looking for something in your career that you 're having a hard time finding, or you 're knocking on doors and they 're not opening, an internship might be the next step for you. If you do some careful planning and research, you can do an internship at any point in your career and any time of year.

Here are three new ways to think about an internship:

Internships allow you

to change fields

Josh Rau just moved to Madison from Boston and he 'll be starting a graduate program in energy engineering at UW-Madison the fall. But he 's taken an internship for the summer at RMT, an engineering and consulting firm in Madison, where he 'll focus on researching renewable energy alternatives.

Rau sees the internship as essential to making himself employable: "My degree is in physics, " he says. "So I can 't just get into the renewable energy sector with that degree. " He is well aware that today, just having a degree is not enough to get a choice job in your field.

Eighty percent of students have an internship under their belt by the time they graduate, so you 'll probably need one just to get a level playing field for yourself. "It 's very difficult to get into a new field without having some type of experience to launch off of, " Rau says. "You have to meet people in your field to get some references and some experience. "

Internships differentiate you from the pack

The toughest internships to land are summer programs in banking and structured, rotational programs in ad agencies and big consumer product companies. Often these internships are as difficult to get into as the very best universities, and once you get one for example, in Goldman Sachs you are earmarked no matter where you go as someone who made it to the very top in a competitive environment.

Those internships require finished applications in November and December, and many candidates spend the year before applying doing related activities in order to make themselves more appealing in the applicant pool. So if you are thinking of getting those top internships for 2009, now is the time to start positioning yourself by the work you choose to take on for the summer and the fall.

Internships give you a chance to test your skills in a new field

A good internship is structured so that you learn about the field and about yourself. You can research the company to find out if it 's known for creating effective internship programs, or you can approach a company with your own idea for an internship.

This second option is especially good for someone who graduated from college a while ago and does not fit the profile that the most structured internship programs are looking for. If you have a good sense of the skills you bring to the table, and a good sense of the skills you 'd like to learn, you 'll be able to make your age work to your advantage by approaching a company and outlining an internship where both of you benefit.

Additionally, an internship gives you a way to test the waters to see if this is really the right fit for you. Research from Daniel Gilbert, professor of psychology at Harvard, shows that humans are particularly bad at predicting what we will enjoy. This is a great trait to keep us resilient -- we are able to convince ourselves to look forward to life even when life hands us a really raw deal. It 's what keeps us from self-destructing, really.

But this trait also means that we are very poor at predicting what life will really be like for us, so we need to try a lot of paths for a career before we know what is really a good fit. So you could say that internships are a perfect workplace adaptation to the human condition of personal ignorance.

Penelope Trunk is a national career columnist who took her own advice about finding a work-life balance and moved to Madison from New York. She founded three companies and is the author of "Brazen Careerist: The New Rules for Success. " Read her blog at http://penelopetrunk.com.