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CORBA stands for Common Object Request Broker Architecture. CORBA is a mechanism that allows applications to invoke object methods that will execute on remote systems. CORBA isn't limited to any single platform, or language. CORBA systems are written in C++, Ada, Java, and other languages. This makes it more interoperable than remote procedure calls and remote method invocation.

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Here's a few rules of thumb : 

When you wish to use services that are running on remote machines (distributed systems) 
When you have a heterogeneous networking environment, containing systems that aren't capable of supporting JVMs because a port is not yet available 
When you want your applications to be accessed by other systems written in C, C++, Ada, Cobol, and other languages (including Java) 

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Third party class libraries allow you to write CORBA application clients and services in earlier versions of Java, but support for CORBA is also included with the newly released Java 2 Platform. Clients and services can be written (though an extra download of the idltojava tool is required). For more information on Java IDL, see "Java and CORBA - a smooth blend".

http://www.javacoffeebreak.com/articles/javaidl/javaidl.html 

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The nameservice can be started by running the tnameserv command, which should be located in your Java 2 binaries directory. Remember however that this service will run continuously, so you'll need to run it in a separate console window.