Around January 10, Microsoft released "Configuring Active Directory to Back Up Windows BitLocker Drive Encryption and Trusted Platform Module Recovery Information," a long-winded name for an executable file that's really a ZIP archive. This news is important because it's the final piece in the BitLocker puzzle.
BitLocker is the Windows Vista Enterprise and Vista Ultimate feature that lets you encrypt your entire C drive—an extremely useful feature for those of us who spend much of our lives walking around with laptops that contain important business and personal information. BitLocker uses an excellent encryption algorithm called the Advanced Encryption Algorithm (AES). You can use AES with either a 128-bit or 256-bit key. (I'd go with the 128-bit key, the default, unless you're walking around with the launch codes for the Peacekeepers on your laptop.) More important than the size of the encryption keys, however, is the question of where they're stored—and where they're backed up. If the hardware that holds the key gets damaged, then you don't have access to your laptop anymore, unless you've somehow backed up those keys. . . .