Torpark is a free anonymous web browser. It sounds good:
A group of computer hackers and human rights workers have launched a specially-crafted version of Firefox that claims to give users complete anonymity when they surf the Web.
Dubbed “Torpark” and based on a portable version of Firefox 18.104.22.168, the browser will run from a USB drive, so it leaves no installation tracks on the PC. It protects the user’s privacy by encrypting all in- and outbound data, and also anonymizes the connection by passing all data through the TOR network, which masks the true IP address of the machine.
From the website:
Torpark is a program which allows you to surf the internet anonymously. Download Torpark and put it on a USB Flash keychain. Plug it into any internet terminal whether at home, school, work, or in public. Torpark will launch a Tor circuit connection, which creates an encrypted tunnel from your computer indirectly to a Tor exit computer, allowing you to surf the internet anonymously.
More details here.