Advice for educators who want to video conference with other classes and experts

I just did a workshop with innovative NYC educators where they learned how to do free video conferencing. Now they want to find other schools and experts with whom to video-conference.I'm sure there are things out there like this. What do Classroom 2.0ers suggest as a smart way to do this? Please let me know ad if you would like, visit this question on our learning network here.