Am I responsible for getting the students to the host families?

No. That will be worked out between each student and host family.

Who will provide transportation for the student(s) once they are in town?

This depends greatly on the area you live in. Some host families will allow student(s) to use their car occasionally, or will be able to drive the student(s) when necessary, but in general, the student(s) will have to provide their own transporation. This means that a student who does not take his/her own car and is working for an organization that is not accessible by public transportation must live with a host who has specified that s/he can drive the student(s) or let them borrow a car. You might want to assist the student(s) in finding car pools to and from your organization.