Here is some infor from a nice site edutopia.
“Classroom wikis, student podcasts, and Google Earth’s many functions are all fairly established ways for students and teachers to share information and work together across many time zones.
Until recently, a class wiki had been the main communication tool for the Flat Classroom Project.
But newer tools, almost all of them cheap or free, are increasingly popular among those in the know.
This year, for example, the Flat Classroom Project has started a Ning — a free,
private social-networking page with audio and text and video-uploading abilities —
that allows students to introduce themselves and exchange information.
The Ning provides a channel for interactions among students that were once done
via email or MySpace, allowing teachers and other students to better experience
what everyone else is doing.
“The connecting piece is the most difficult part,” says Davis about getting the
students to work together on different clocks. “Last year, we were doing it over
email. We couldn’t supervise.Here, all the group dynamics are out in the open
for the teachers to observe.”
To schedule planning and presentation time, they use a free Web program called
AirSet, which can synchronize existing calendar systems (such as Microsoft Outlook’s)
and work between time zones.
For video, some insiders like FlashMeeting, a free service that has been described as a videoconferencing version of YouTube and that low-bandwidth schools can use to communicate online. Another free tool is Ustream.tv, which offers live video streaming anyone can watch online and chat about simultaneously. “