This week's book giveaway is in the OO, Patterns, UML and Refactoring forum. We're giving away four copies of Refactoring for Software Design Smells: Managing Technical Debt and have Girish Suryanarayana, Ganesh Samarthyam & Tushar Sharma on-line! See this thread for details.
A web server handles HTTP requests for web content. An application server provides a suite of services defined by the JEE specification. Since application servers provide a Servlet container (that will include a web server) they come already integrated, but you can also integrate an external web server with an applciation server.