Marsha,
You bring up an interesting point. Different institutions define internships and externships differently. In some programs, they are a requirement of the curriculum, some are paid positions and some are voluntary. All provide useful experience to the student. Externships that provide a "working interview" is great experience for the student, it increases their self- confidence and may lead to a paid position after graduation. To further this discussion, can you be more specific as to the differences between the internship and externship at your organization?
Sheri Leach