Your options are rather broad, so you should focus on your primary interest. There are a myriad of methodologies firms deploy in order to manage their global operations effectively and efficiently.

Essentially, all Fortune 500 companies are now global, and as such will retain employees who have a degree of subject-matter expertise in global business to manage those operations. If you desire to remain in the US, there are opportunities in practically any business discipline within such a company, such as marketing, sales, finance or operations.

If your interest is living and working abroad, you will probably have an entry level position within the international managment sector of your chosen company before you are placed abroad. It will also be extremely beneficial, if not mandatory, to be fluent in one additional language other than english (and there are many schools of though as to what that language should be). There are still some major corporations based in the US that have a distinct international business division that concerns itself with every aspect of their foreign operations, including a cadre of managers who are especially adept at working in foreign environments.

Lastly, and assuming you are seeking an undergraduate degree, I believe it is imperative to find a program that requires at least one work/study term abroad. I am aware of too many international business curricula that teach how to do “American” business in another country, but once in-country you realize how much the culture and norms of your assigned location are integral to conducting business successfully.