There are many useful tools out there that help increasing your security and privacy:

• All-in-one
  • {D}igital{A}nonymous{D}emocracy, aka D.A.D., is a collection of commonly used software that is pre-configured to use Tor. It includes Firefox (Web), Thunderbird w/ PGP encryption (E-Mail), Pidgin w/ OffTheRecord? (IM), and Azureus (File sharing). It uses TOR with Vidalia as the controller. D.A.D. was designed to be portable so you can take it anywhere on a USB drive.
• Anonymous Mail and News
  • QuickSilver Mixmaster client for Windows. Possibly the most newbie friendly.
  • Jack B Nymble Mixmaster client for Windows
  • News2Remail Mixmaster client/local proxy. For anonymous news posting using news reader software.
• Erasing Data
  • Eraser Windows meant to securely delete data from the disk.
  • Darik’s Boot and Nuke A self-contained boot disk
• Instant Messaging
  • TorChat is a peer to peer instant messenger with a completely decentralized design, built on top of Tor’s location hidden services, giving you extremely strong anonymity while being very easy to use without the need to install or configure anything. TorChat just runs from an USB drive on any Windows PC. (It can run on Linux and Mac too, in fact it was developed on Linux with cross platform usability in mind from the very first moment on, but the installation on other platforms than Windows is a bit more complicated at the moment). With help from the author and testing from the project we got the application to work. We have our own installation page on TorChat.
  • Off-the-Record Messaging (OTR) Cryptographic protocol that provides strong encryption for instant messaging conversations. In addition, it provides authentication, deniability and forward secrecy. To communicate privately using OTR, the messaging client needs to support it natively or by plugin, or a local proxy can be used.
• Mail Encryption
  • GnuPG delivers encryption. It uses the OpenPGP-standard so that receivers of e-mail can check if someone really sent an e-mail and it didn’t change while travelling the internet. Meanwhile eavesdroppers can’t read what actually has been sent across the net. However if someone sniffs the traffic they do know who is e-mailing whom. Most Linux-distributions have the software pre-installed. Supported platforms: Linux, Mac OS X, Risc OS, Solaris and Windows
  • Enigmail is a Thunderbird plugin for GnuPG
• Storing data
  • Truecrypt is a program that can store data in containers with strong encryption. A cool feature is that it is possible to have a secret container in the regular container. So when you’re forced to hand over the password of the container only marginal-important data will be handed over to the attacker. At this point the Windows-version also offers an option to encrypt an entire system so a lost laptop doesn’t mean exposed data. The software can also encrypt a regular disk or partition of a disk. That is useful for USB-sticks or external disks. Supported platforms: Linux, Mac OS X and Windows. Features may vary per operating system. In episode #1 of the Small Sister Podcast we explain how you can encrypt an entire Windows-disk.
  • The Freenet Project or Free Network Project delivers tools to store data on the internet. The system is peer-to-peer and every user is part of the online storage. Everything is encrypted and devided over multiple computers. It aims to fight censorship online, since one cannot take documents offline.
• Surfing:
  • Tor is software that helps you be more anonymous online. It redirects your traffic through a number of online nodes. By doing this it seems that your traffic actually comes from a total different location. When travelling through the TOR network the data is encrypted. When it goes to the destination it isn’t. Beside browsing you can set it up in such a way that it works for e-mail, instant messaging or other services as well. Supported platforms: Linux, Mac OS X and Windows.
  • TODO: Firefox plugins: Adblock.
  • JanusVM is a virtual machine that runs Tor. You simply create a VPN connection to JanusVM and all your internet traffic is routed over the TOR network. This is extremely useful for applications that do not support using a socks proxy. Because all your TCP traffic is routed over TOR, and all UDP/ICMP traffic is dropped, it is very secure and helps prevent side channel attacks that could reveal your true location.
  • FreeCap Windows. Transparently redirects connections from any program through a SOCKS server. This way, software that do not support SOCKS natively can still have their connections routed over Tor.
  • SquiggleSR is a Firefox add-on which generates personalized queries to search engines to deceive search engines and protect user’s privacy. Queries are generated using personalized keywords and clicks are randomly simulated on non-sponsored results. SquiggleSR uses several sources of keywords, including RSS flows and search engines statistics (Zeitgeist, Yahoo ! Buzz…). Last version introduces cookie tracking deception and supports Firefox 3 beta5.
• Telephony
  • Zfone Project is software that integrates with Voice-over-IP-applications and offers phonecall encryption. The software integrates with open standards like the Session Initiation Protocol (SIP) and can’t support Skype since it is a closed system. Because the encryption is done at computerlevel eavesdropping is useless. The software has been created by Phil Zimmermann, who once made PGP as well. Supported platforms: Linux, Mac OS X and Windows. When downloading you have to have a working e-mail addresss, because Phil needs to prove that he isn’t exporting encryption software from the US to forbidden countries.