I saw this a few months ago and now that its term paper time at school I signed up. Its amazing.
Basically you install this, it puts a folder on your PC and you can install it on as many PC's as you like (MAC Windows Linux).
It keeps the folders sync'd over the Internet(you dont even have to click and tell it to) and you can download/upload from their website so you pretty much have your files ANYWHERE with an Internet connection and when you get home the file will have all the changes you made to it.
There is a free plan that gives you 2Gigs of storage and you can earn more by doing stupid things like downloading their desktop client or clicking through a tutorial.
Check it out at
https://www.dropbox.com/
Oh one more thing that is awesome about this, if you have a huge zip file that is too big to email, you just have to drag it to a "Public" folder in your Dropbox folder and you can right click it and get a URL to send in a email.
Hope you get as much use out of it as I do.