International consulting engineering firms usually have international projects which they handle from time to time. However, most cases, they only sent people with some degree of experience. They do ocasionally sent some junior engineers to help the resident staff, if it is a large project. If you are thinking about an engineering career overseas, you should plan from the start. Companies like Harza, Parson Brickerhoff, Black and Veatch, URS (Woodward Clyde), Ralph M. Parsons, Fluor Daniels, Bechtel, Montgomery Watson, etc usually have international operations. You will have to start from the bottom up... in the US.  As you start, you may as well try to get your PE at the same time. By the time you get your PE, and you indicate an interest to gain experience overseas, then you should discuss this with your supervisors. These big companies have jobs worldwide, and need almost every type engineers for supervision of construction projects. You can look their websites, through links at Engineering News Records (http://www.enr.com).
Hope this helps

The comments from georam are right on the money.  One often overlooked opportunity is the scheduling of the FE, or E.I.T. exam.  You may generally take this exam, a prerequisite for the P.E. exam, while still attending college.  This is the perfect time to take this test, since it is a test of basic engineering knowledge.  The longer after your collegiate career you wait before taking this exam, the more likely lack of use will rear it's unforgiving head.  You will also, upon satisfactory completion of this phase of your career, be able to accept out of country work assignments without conflicting with a set FE testing schedule.