Here is a great little product, TrueCrypt [
here], that offers you top shelf on-the-fly data encryption to an encrypted disk. The software works on Windows XP/2000/2003 and Linux, so you can have an encrypted container on removable media and mount it just about anywhere. This is an excellent little program for data protection, fully integrating into the OS so that your encrypted container looks like just another disk when it is unlocked.
Read full article: 'TrueCrypt - Free Open-Source Disk Encryption'