<p>I know something about Java but completely new to Enterprise Java. I'm trying my hand with NetBeans 6.1 and GlassFish Application Server. 
Please guide me to some resources which tell me actually what java enterprise applications are, how they are different from normal java classes etc. </p>

<p>Also which is the best application server to use (on Linux)?</p>

The Java EE 5 Tutorial
- read online or as pdf
EJB 3 in Action
- great book that covers everything you need to know
I have also recently started with Java EE and I have only used Glassfish/Sun Application Server so far, but from what I understad from my colleagues at work and what I have seen so far Glassfish seems to be the the best choice at the moment.