We have done a few here at EHMIS - its where two teachers get paired up and they share books they are reading with each other.  Typically, each class chooses 4 or 5 books that they are going to give a book talk about, and then they take turns presenting.  We usually include some "free" conversation time as well for them to just talk about where they live, what they like to do, etc.    Here is the link for that: http://www.twice.cc

 

E-Missions are scenario based learning activities - very much like virtual field trips.  Most do cost $$, but they are worth it in my opinion. SWSD has particiapted in Operation Monserrat,  Storm-E, and Cyber Surgeons  http://www.e-missions.net/   

Museums, Science Centers, Government agencies (park service, forest service, etc.) are also places to find great video conferences.  If you think about where some of these folks used to go for field trips, you may find that they do a Video conference.  Most of these also have a fee.  

Links: 

Here is another organization I have heard of - Global Nomads group.  They do a lot of world issues.

Here is a sample of a VC they are running this spring: http://gng.org/programs/program/the-japan-earthquake-one-year-later-2/   
Can't find a specific price - but it looks like they can run from $0 - $300