Using Encryption programs:
There are many encryption packages available, with many features. For the purposes of leaving information to your heirs, you don't really need anything fancy, and we can recommend some packages which are free. If you are a computer novice and feel that you will need technical support, you may want to buy a commercial package. They are generally not expensive, and then you can contact the vendor for support. We do not provide technical support for encryption; there are many packages out there and we don't have the manpower.
If you want a recommendation, we suggest either PGP or 7-zip. Both are free and both can produce a self-decrypting archive (SDA). What is an SDA? An SDA is a file that contains an encrypted version of your document along with a small program. The file looks like a program file, that is, it has a .exe suffix after the file name. The advantage of an SDA is that your intended recipient does not have to install any programs in order to read the document. All they have to do is double click on the SDA. A window will pop up and ask them for the password. Once they type in the password, a decrypted version of the document will appear in the same folder.
PGP (Pretty Good Privacy)
PGP has been around for over ten years and is a solid product, it has polished documentation, and you can also purchase the latest version if you want technical support. If you download the free version, they will try every which way to cajole you into purchasing it, warning that important features will be disabled after 30 days. However, the feature that lets you create an SDA is permanant.
To obtain a copy of PGP follow this link: http://www.pgp.com/downloads/desktoptrial2.php
They ask you to fill out a form and then they email a download link.
Once you have installed PGP you will be able to right click on any file or folder, and you will see a PGP option in the menu. Mouseover the PGP option and you will see a Create Self-Decrypting Archive option. You are then prompted for a password. The archive file will appear in the same directory with the same name as the original, but with a .exe extension.
Another nice feature in PGP is the PGP shredder. After you have created your encrypted file, you may wish to destoy the original so that if anyone gets access to your computer, they cannot read this information. If you simply delete a file in Windows, it is not really deleted at all, but is simply placed in your trash bin. Even if you empty the trash bin, the file can still be retrieved by not particularly clever people using special programs. However if you drag a file to the PGP shredder, it is quite irretrievably deleted. You can also do this by right clicking on any file and choosing PGP > Shredder.
7-zip
7-Zip is actually a file archiving program that you can use to compress files (place a directory full of files into one file and squeeze them so they take up less space). Its open-source (i.e. free) and also contains a nice SDA feature.
You can obtain 7-Zip from the follow link: http://www.7-zip.org/
For most people, just download the 32bit .exe version and install the program on your machine. When you run 7-Zip, you will need to navigate to the folder that contains your documents. Click once on the folder or file you want to encrypt to highlight it, then click on the ADD button at the top. 7-zip will bring up a dialog box showing your file or folder name with a .7z suffix. Check the box that says create SFX archive (basically the same thing as an SDA), enter a password in the password box, and click OK. A file with the same name as your file or folder, but followed by .exe will now appear in the same directory.
7-zip does not include a shredding feature, so you might want to get a free one such as eraser
http://www.heidi.ie/eraser/
Another free encryption program to consider is Kruptos 2, at http://www.kruptos2.co.uk
Securezip from http://pkware.com is only $29.95 and is one the most established programs on the internet (these are the people who invented the .zip format)