Well this is what I found, it's to bad it's not write with XP or Vista read only. I going to have to format the drive again because I need it for XP too.
BitLocker protection on removable drives is known as BitLocker To Go. When a BitLocker-protected removable drive is unlocked on a computer running Windows 7, the drive is automatically recognized and the user is either prompted for credentials to unlock the drive or the drive is unlocked automatically if configured to do so. Computers running Windows XP or Windows Vista do not automatically recognize that the removable drive is BitLocker-protected. With the BitLocker To Go Reader users can unlock the BitLocker-protected drives by using a password or a recovery password (also known as a recovery key) and gain read-only access to their data."