Selenium Server, the 2.0 blend of Selenium RC and Webdriver, is the latest in CI Testing goodness from the Selenium project and SeleniumHQ.  During my experimenting with trying to get Selenium to take scripts made in the Selenium IDE and run them with the new selenium-server-standalone-2.0.0.jar via the Jenkins Seleniumhq Plugin on a Jenkins/Hudson slave, I had a few different issues.  My primary problem was getting *iexplore tests to execute from a Jenkins/Hudson slave node.  The slave is running as a service started as a domain user instead of Local Service.  The slave has to run as a domain user because the Jenkins slave is also doubling as a Windows build server running off a Linux master.  The goal was to test with Firefox 5 and Internet Explorer 7 in a Windows Server 2003 R2 x64 environment.  In the end, I could only get *iexplore tests to run reliably by using Window’s automatic logon and then launch the Hudson/Jenkins slave as a startup shortcut which was just:

javaws http://hudsonhost.local:8080/hudson/computer/slave-agent.jnlp

I believe this will also work with nearly any other Windows distribution up to the latest 7/2008R2 series. It was undesirable to run the Slave service in this way however it may just be what is necessary to test older software with a Windows Server 2003 platform.  This approach locks you out of the console of the server, but you can leave the user with just user privileges and then remote in to administer if needed.

By the way, Firefox 5 ran flawlessly as a domain user after creating a Firefox profile for Selenium.