Dropbox is a great little (free!) tool for sharing files.
When you put a file on Dropbox, you can access it from any other computer where the software is installed. When you edit, your changes are saved in both places, so you no longer have to worry about multiple versions of files or carrying a flash drive between two computers.
You can also use it to share files with other users. Have you ever tried to email a file to someone and it was kicked back to you because it was too large? Dropbox solves this problem for you by giving you a folder online for you to share with other people you select. Files are also backed up for free (up to 2GB).
So, check it out here.