In this piece Tony Bradley provides some great insight into how Windows BitLocker “drive” encryption works in Vista and Windows 7. Actually BitLocker is not drive – or whole-disk – encryption after all…As Tony states it’s more like whole-volume encryption.
Keep this in mind when securing your laptop and mobile drives. This could create a pretty serious false-sense of security that everything’s locked down when indeed it’s not. Same as the false-sense of security Windows EFS has created over the years.
Anyway, the piece is a good read providing a nice overview of how BitLocker works and is worth checking out.