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.
SAR files are Service ARchives. Like their abbreviated form, the simple *-service.xml file, they represent services that are to be loaded into the JBoss microkernel. These archives/files are specific to JBoss, but the services they represent are not necessarily so.