VaultletSuite 2 Go is privacy protecting software that installs on your hard drive or your thumb/USB drive. It uses Open Source 2048 bit RSA public key and 256 AES encryption, and provides easy-to-use (transparent) encrypted and controllable email and password protects important files.
Portable Thunderbird is the popular Mozilla Thunderbird email client packaged as a portable app, so you can take your email, address book and account settings with you.
TrueCrypt is a free open source on-the-fly encryption (OTFE) program for Microsoft Windows XP/2000/2003 and Linux. It allows one to create a virtual encrypted disk within a file and then mount it as a real disk