Everyone has personal data on the PC, which can not be accessed by others. For example, a credit card number or password access. TrueCrypt encrypt and hide data. To that end he created a container that can be protected with up to 448 Bit encryption.
TrueCrypt mengintegrasikannya into the system as a virtual-drive. The tool also can encrypt the entire partition. So it works like that BitLocker is only available in the Ultimate version of Vista.
Info : http://www.truecrypt.org
Download : TrueCrypt