TrueCrypt is an open source encryption package for Windows and Linux, with plans to port it to other systems as well. It allows you to create file systems that transparently encrypt the data stored to them. Since it is open sourced it has been well reviewed and can be ported to new platforms, not something that can be said for Microsoft’s EFS. Another cool feature of TrueCrypt is “plausible deniability” encryption. A hidden volume can be stored in a standard volume using a different password, allowing the user, if forced, to giveaway the outer volume password while keeping the hidden volume password secret.

You can download TrueCrypt from:

The video is located here: