Apple has recently patented a virtual "locker" for encrypted data storage in Mac OS X. Speculation is that this new feature will work with Apple's revamp of MobileMe and heavily integrate with iOS.
This virtual vault will further Apple's focus on cloud-based technologies and probably work like Dropbox. Files dropped into said folder on OS X will sync with Apple's cloud-based storage service (probably replacing iDisk) and encrypt data as it is uploaded to the cloud.