Google Docs- www.google.com
You can use Google Docs to collaborate with your classmates. All of you may be looking at the same document at the same time and seeing each others edits and typing in real time.
This is a very powerful collaboration tool that can be used anywhere as long as you are connected to the Internet. Your documents in Google Docs will never be lost and always accessible 24/7.
Skype - www.skype.com
Skype is a free web tool that will allow you call your classmate's computer for free. You are able to talk to your classmates as you collaborate on assignments and your final project. This service is free as long as you do not call a cell phone or house phone.