This week's book giveaway is in the OCMJEA forum. We're giving away four copies of OCM Java EE 6 Enterprise Architect Exam Guide and have Paul Allen & Joseph Bambara on-line! See this thread for details.
In brief, if you're using the ApplicationResources.properties file in your application to display labels on your pages, use LookupDispatchAction. Otherwise, use DispatchAction. See Struts 1 tips 1 and 2 in this link for a more detailed explanation of each.