Skype

I have to mention that Skype is a good program, and has many uses. For some it is just a cheaper way to keep in touch with relatives far away, for others it is a collaboration tool. I have used it for both. I have used it to get through school work, and have called friends/family across the country. If only I could get my Great Uncle to install it in the UK.
As far as collaboration goes people can use it to get work done or just bounce ideas about randomness.
Gotta love the random.

http://www.skype.com/intl/en-us/home