I’ve posted about Selfcast. In fact, it also made it onto The Best Web 2.0 Applications For Education — 2008. It lets anyone with a webcam immediately broadcast over the web for free, and anyone (without registering) can watch and also participate via live text chat. The presentation is also recorded and can be watched in the future, too.
I just learned about a similar web tool called Zaplive TV. In fact, it almost seems the same, but I haven’t really explored it much yet.
This might be an option to consider when working with international sister classes (assuming time zones worked out). I still have to think about advantages and disadvantages of something like this compared to a tool like MeBeam and Tokbox, two online video conferencing sites. They both allow you to just use microphones for audio if you don’t have a webcam.
On advantage I can see for Selfcast or Zaplive is that less extra equipment would be needed — you would only have to have one webcam on one end, and wouldn’t need mikes for text chat. And more students could be online at the same time. Obviously, not having the ability to make audio comments would also limit, to an extent, the student interaction. But it might be worth looking at as an option.