Encrypting data on your desktop and flash drive for free

Here is a software (open-source) which is free to download (see license for details) - TrueCruypt. This software allows you to encrypt the data in a folder or file in your desktop. Couple of really cool features that I like about this software are

• It can create a virtual disk in your computer that is encrypted. This disk will be visible to software running on your computer as a regular disk
• This could be used to encrypt data in your USB flash drive.
• and ITS FREE!!!