Skype in the Classroom:

Skype in the classroom is a free community to help teachers everywhere use Skype to help their students learn. It’s a place for teachers to connect with each other, find partner classes and share inspiration. This is a global initiative that was created in response to the growing number of teachers using Skype in their classrooms.

Check out the Projects section, a clearinghouse for various projects, to get an idea of what other educators are doing with Skype. You can sort by age group and subject area, and even search for guest speakers.