FolderShare

How to Use FolderShare to Transfer Big FilesSometimes you need to send or receive files that are very large in size, even after they're zipped. Your ISP or the sender's/recipient's on the other end may not support file sizes that are over a certain limit (usually a couple of MB), and you might not want to set up an FTP server for security reasons. One solution is to use FolderShare, a file synchronization service that was recently acquired by Microsoft and is now in beta as part of the Windows Live family. You can download the software for both Windows and Mac OS X. Here's how to use it once it's installed:
If you haven't used FolderShare before, on the Welcome screen, click "I don't have a FolderShare account."
On the New Account Information page, choose a nickname and password and type in your email address. You also have to check a box certifying that you're over 13 years of age.
The software will connect to the FolderShare server and create your account.
On the "choose a computer name" page, the default is your computer's name on the network. Accept the default and click Finish.
Now you'll see a flashing icon in the system tray. You can click a FolderShare library if you've been invited to share one, or click My FolderShare to go to the web site and set up a folder to share, sync your folders, share your folders with friends on the Internet, or access your files. FolderShare operates like a private P2P program. Those you invite can share items in the folder(s) you designate to share, but can't access anything else on your computer.