A professional association offers a setting for members in the same profession to join together to network, stay abreast of what's new in the field and to share information. Association officers are active in legislation that regulates their profession or industry.
Association websites might also be helpful if you are only in the information-gathering phase of career information. You'll probably find an association or union for just about any occupation.
Here are a few examples of a variety of professional associations where you can gather information about your career choice. Associations are easily found on Google by searching for (name of career or occupation) AND "professional association"