There's a new "Secure" browser out there, based on Firefox, called TorPark.
"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. How much does Torpark cost? IT'S FREE."
The end result is that the user IP seems to be changing every few seconds when accessing the target site (since it changes an "Exit TOR machine" every few seconds).
It's important to realize that the encryption only takes place between your own machine and the exit computer, but not between the exit computer (your proxy to the world) and the target site, so if you're not using SSL encrypted pages, you can still have your passwords and other security info stolen.