8 seems to lack the BitLocker that came with 7 Ultimate. I need to research this a bit.
Windows users can also benefit from TrueCrypt which is a Linux service as far as I know and it can also be set to load before Windows. I have used it within XP, though, to encrypt data folders and also my SD cards and flash drives. Ubuntu 12.10 encrypts your entire installation if you so prefer but you can still encrypt your home folder separately.
Bitlocker is available with Windows 8 Pro:
http://windows.microsoft.com/en-ZA/windows-8/bitlocker#1TC=t1