This week's book giveaway is in the OCPJP forum. We're giving away four copies of OCA/OCP Java SE 7 Programmer I & II Study Guide and have Kathy Sierra & Bert Bates on-line! See this thread for details.
Hudson doesn't magically build your project. It only automates the execution of the build process that you already have - whether it is Ant based or Maven based.
So if you build your project using an Ant script, you can configure Hudson to execute that script automatically or manually. It can grab the latest code and execue test cases. Check out the Hudson website to learn how to do that.