Tor Project: Anonymity Online. Tor is free software and an open network that helps you defend against traffic analysis, a form of network surveillance that threatens personal freedom and privacy, confidential business activities and relationships, and state security. 

Tor is a network of virtual tunnels that allows people and groups to improve their privacy and security on the Internet. It also enables software developers to create new communication tools with built-in privacy features. Tor provides the foundation for a range of applications that allow organizations and individuals to share information over public networks without compromising their privacy.

Pretty Good Privacy (PGP) is a popular program used to encrypt and decrypt e-mail over the Internet.

It can also be used to send an encrypted digital signature that lets the receiver verify the sender's identity and know that the message was not changed en route. Available both as freeware and in a low-cost commercial version, PGP is the most widely used privacy-ensuring program by individuals and is also used by many corporations.

Developed by Philip R. Zimmermann in 1991, PGP has become a de facto standard for e-mail security. PGP can also be used to encrypt files being stored so that they are unreadable by other users or intruders. Read more about PGP - here.

Use guerillamail.com. Guerrilla Mail gives you a disposable email address. There is no need to register, simply visit Guerrilla Mail and a random address will be given. You can also choose your own address.

You can give your email address to whoever you do not trust. You can view the email on Guerrilla Mail, click on any confirmation link, then delete it. Any future spam sent to the disposable email will be zapped by Guerrilla Mail, never reaching your mail box, keeping your mail box safe and clean.

For chat, use Pidgin. Pidgin is a chat program which lets you log in to accounts on multiple chat networks simultaneously. This means that you can be chatting with friends on MSN, talking to a friend on Google Talk, and sitting in a Yahoo chat room all at the same time.

Pidgin runs on Windows, Linux, and other UNIX operating systems.