Where do I find information about job opportunities in the field I want to study?

I find that the best place to get information about a job, is searching for job postings. Almost all job postings will provide you with a list of required and preferred skills as well as give you a description the job.

Another good resource is contacting the school you're thinking about attending. Most of the professors that teach the degree related courses have experience doing the jobs and are more than glad to share that information.

I would also recommend talking with your school counselor.

Hi,
Great answer above from Jeremy, I will add that I have always learned a lot from job posting websites...even when I am not searching for a job, I sometimes do job searches to stay in touch with the job market and what jobs are out there. Example, using indeed dot com (the best job search site - I think), you can search for jobs in specific locations, with specific companies or in specific career fields.
Then when I find a company I do not know a lot about, I go to their website and look for the "about us" tab and/or career/employment opportunities.
Hope this helps...good luck! :)

LinkedIn can be a good resource for your search. Once you create a free account, you can create a 'job search agent' where you can specify specific industries or functions of interest. Indeed.com is another option. Think creatively about what terms you search for on these sites. Let's say that you are majoring in business. You'll need to specify what types of roles you are looking for. Finance? Accounting? Marketing? Banking? All fall into the broader bucket of business. Also keep in mind that the jobs you apply for may not be necessarily related to your field of study / major. I studied political science and joined a management consulting firm after graduation. I encourage you to think about the type of work you want to do rather than just roles related to your major.