These are some good websites that will help you find online partners -
For your students:

"Welcome to the Internet's largest global community of connected classrooms!
Safely connect, collaborate and learn using our leading protected email and blog solutions for schools."
The IBO is trialling e-pals this year, with a view to to implementing hosted learning community for IB schools in 2010.

Other global projects can be found at

For teachers:
You can join PYP Threads, an online group, "... a place to weave, unravel, and re-weave PYP threads into fabrics of communication

Another good group is Classroom 2.0, which is "a social network for those interested in Web 2.0 and collaborative technologies in education".