Tor Browser Bundle
The Tor software protects you by bouncing your communications around a distributed network of relays run by volunteers all around the world: it prevents somebody watching your Internet connection from learning what sites you visit, it prevents the sites you visit from learning your physical location, and it lets you access sites which are blocked.
The Tor Browser Bundle lets you use Tor on Windows without needing to install any software. It can run off a USB flash drive, comes with a pre-configured web browser and is self contained. The Tor IM Browser Bundle additionally allows instant messaging and chat over Tor. If you would prefer to use your existing web browser, install Tor permanently, or if you don't use Windows, see the other ways to download Tor.
Download Tor Browser Bundle and Tor IM Browser Bundle
To start using the Tor Browser Bundle or Tor IM Browser Bundle, download the file for your preferred language. This file can be saved wherever is convenient, e.g. the Desktop or a USB flash drive.
If you have an unreliable Internet connection, it may be easier for you to download the bundle edition which is split up into smaller parts.
Tor Browser Bundle for Windows with Firefox (version 1.2.2, 15 MB)
Tor IM Browser Bundle for Windows with Firefox and Pidgin (version 1.2.2, 24 MB)
See our instructions on how to verify package signatures, which allows you to make sure you've downloaded the file we intended you to get. Also, note that the Firefox in our bundle is modified from the default Firefox; we're currently working with Mozilla to see if they want us to change the name to make this clearer.
Extraction
Download the file above, and save it somewhere, then double click on it. Click on the button labelled "..." (1) and select where you want to save the bundle then click OK (2). At least 50 MB free space must be available in the location you select. If you want to leave the bundle on the computer, saving it to the Desktop is a good choice. If you want to move it to a different computer or limit the traces you leave behind, save it to a USB disk.
Click Extract (3) to begin extraction. This may take a few minutes to complete.
Usage
Once extraction is complete, open the folder Tor Browser from the location you saved the bundle.
Double click on the Start Tor Browser (4) application (it may be called Start Tor Browser.exe on some systems.)
The Vidalia window will shortly appear.
Once Tor is ready, Firefox will automatically be opened. Only web pages visited through the included Firefox browser will be sent via Tor. Other web browsers such as Internet Explorer are not affected. Make sure that it says "Tor Enabled" (5) in the bottom right corner before using it. To reduce the risk of confusion, don't run Firefox while using the Tor Browser Bundle, and close existing Firefox windows before starting.
If you installed the Tor IM Browser Bundle, the Pidgin instant messaging client will also be automatically opened.
Once you are finished browsing, close any open Firefox windows by
clicking
on the 
(6).
For privacy reasons, the list of
webpages you visited and any cookies will be deleted.
With the Tor Browser Bundle, Vidalia and Tor will automatically close. With the Tor IM Browser Bundle you need to also close Pidgin by right-clicking on the Pidgin icon (7), and choosing Quit (8).
To use the Tor Browser Bundle or Tor IM Browser Bundle again, repeat the steps in "Usage".
Remember that Tor anonymizes the origin of your traffic, and it encrypts everything inside the Tor network, but it can't encrypt your traffic between the Tor network and its final destination. If you are communicating sensitive information, you should use as much care as you would on the normal scary Internet — use HTTPS or other end-to-end encryption and authentication.