Skype - http://www.skype.com/ - with an account you and your students can contact and collaborate other teachers/classes by phone of videocam for FREE. What a collaboration opportunity!

Skype and WIKIS - http://wikiskype.pbworks.com/Skype+in+the+Classroom

Skype in Schools - http://skypeinschools.pbworks.com/Experiences

Watch this amazing video (click on the image) -- about using Skype. Students in this class are in contact with a classmate who cannot attend school because of leukemia.
Learning is Messy
http://learningismessy.com/blog/?p=196

Here is a little booklet the learn the ins and outs of setting up and using Skype. http://www.willard.k12.mo.us/co/tech/Document/skype.pdf

Here is a great YouTube video using Skype in a cross-cultural situation.
http://www.youtube.com/watch?v=7_-n7ZbpwGY&feature=youtu.be&a