Great summary of the best free (as in speech and beer) applications of 2009, including TrueCrypt Free open-source disk encryption (real-time on-the-fly encryption) software for Windows, Mac OS X, and Linux (for Linux I prefer native disk encryption). From the wikipedia:

It can create a virtual encrypted disk within a file or a device-hosted encrypted volume on either an individual partition or an entire storage device. It supports Microsoft Windows, Mac OS X and Linux (using FUSE) and encrypted volumes can be made portable. The version for Windows Vista or XP can encrypt the boot partition or entire boot drive and has the ability to create and run a hidden encrypted operating system whose existence is deniable.

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