Windows Live SkyDrive

Password-protected online file storage. Always available where you need it.

Offers:

• 5 GB of free online storage, available from any computer with Internet access.
• Create personal, shared, and public folders -- you decide who has access to each folder.

Personal

• Use personal folders to back up important files that are only for you.
• Get to your files from any computer with Internet access by signing in with your Windows Live ID.

Shared

• Shared folders make it easy to collaborate with coworkers or classmates.
• You decide how much control each person has over each shared folder. Some can just read what's there: others can add and delete files.
• Everyone who is sharing uses their own Windows Live ID.

Public

• With public folders, anyone on the Internet can view your files, but they can't change them.
• Want to show your public files to others? Just send them a link! Each folder and file has its own web address.

Link:
http://skydrive.live.com/welcomemoreinfo.aspx