One site that was originally set up entirely to support information exchange between teachers and learners in different cultures is ePals, reviewed recently in the New York Times (mostly this article reviews the business model but there are some interesting quotes about the pedagogical approach adopted as well). Not that I have tried this service, but it has been around for a while now, and looks like it might be worth checking out.
According to the article the idea of exchanging information over the internet with students from other cultures is inherently motivating to a lot of the students participating. One teacher comments:
If they were just writing for me, they wouldn’t be as careful. But they’re writing for a student in another country. It’s not drudgery for them. They buy in and they enjoy it.Teachers are using the site to send their students on virtual field trips, where they can learn about the family life and political systems of up to 120 different participating countries (that's a lot!). The site now has 13 million registered participants so it is getting to the point where it could have an impact.
I know that teachers in Hong Kong are always looking for ways to engage their students, and give them opportunities. I'm not aware of many exchanges of this nature though. I wonder how well this kind of collaboration could work in the local scene, or what kind of work would be necessary to make it a success.