Google Docs is a cloud-based office sweet. That basically means that your word processor, presentation maker, and spreadsheet tools are accessible through a website instead of your desktop.
How does that affect you?
You can access your documents from any computer with an internet connection, and you will always have the most up-to-date version of Google Docs as upgrades happen automatically online. It also means that you can share documents with other Google Docs users in real time without ever having to worry about messy attachments.
What does this cost?
Goolge Docs is completely free for educational users!