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.
Tomcat is a servlet container, and thus is well suited for deploying web applications.
Glassfish is a Java EE application server which means that besides providing a servlet container it also provides a bunch of other services such as messaging, EJBs and so on. It is way more than what you need for a web application if you don't plan on using the additional capabilities.