Using WebDriver

From a New Download

There are two downloads that you will generally want to chose:

selenium-server-standalone.jar - This contains the Selenium server (required if you want to use the Selenium 1.x classes) and the RemoteWebDriver server as a standalone jar, that can be executed using java -jar. Note that this JAR contains all of the required dependencies. If you'd prefer to manage the classpath yourself, then download the "selenium-server-XXX.zip" file.
The language bindings for your language of choice. If you're using Java, then download the latest selenium-java-XXX.zip where "XXX" represents the version number. For .Net, the appropriate zip is the selenium-dotnet-XXX.zip.

With Maven

To use the client libraries (the remote webdriver client, ChromeDriver, FirefoxDriver, HtmlUnitDriver, InternetExplorerDriver, OperaDriver, and support libraries) Add the following dependencies to your project:

  <dependency>
    <groupId>org.seleniumhq.selenium</groupId>
    <artifactId>selenium-java</artifactId>
    <version>2.26.0</version>
  </dependency>

If you want to start a selenium server, you will need the following dependency:

  <dependency>
    <groupId>org.seleniumhq.selenium</groupId>
    <artifactId>selenium-server</artifactId>
    <version>2.26.0</version>
  </dependency>

That's it.

From a Fresh CheckOut

Follow the instructions in CheckOut in order to get the latest version of WebDriver.
Run rake without any targets (that is, just run rake) This will run the unit tests too, and if that's not what you want to do, just run: rake all
Figure out which drivers you will need on your project. You'll need at least common, but depending on your needs you may or may not want the drivers for Firefox (FirefoxDriver), Internet Explorer (InternetExplorerDriver), and/or HtmlUnit (HtmlUnitDriver) The JARs for the classes in "org.openqa.selenium" are located in subdirectories of the "build" directory. It should be obvious what is where. The OperaDriver is located in /third_party/java/opera-driver/.
Now, just copy the required runtime libraries and the newly built jars on to your CLASSPATH. Read the build.desc files to figure out what these are.