Although not specifically international, this is an excellent compilation of profession-specific resources on the web. Much of site accessible only to subscribers. Also check with discipline-specific professional associations. The NEA's International Partnerships Office has on its site links to a number of organizations that may consider applications for internships or may offer funding for international activities. Most overseas job sites list plenty of business jobs, though most require experience.
Site has links to chapters worldwide.
An outstanding site for those interested in business. Most jobs require previous experience. Most overseas job sites list plenty of engineering and computer science jobs. There are good links for findng jobs and internships, however, the site does want you to sign up and become a member before using their resources. Not only environmental, this outstanding site will be of interest to people in a number of fields, from policy and international relations to development and nongovernmental organizations.