You have two options in order to consume an already available web service, like Amazon web services.
You can call use Dispatch class and its related class in order to call the service dynamically without having any pre-generated client stub. this way you have more control on how you want to create your soap message....
you may take a look at http://www.ibm.com/developerworks/websphere/library/techarticles/0707_thaker/0707_thaker.html
for more information on this method.
The other way is to generate a client stub using wsimport
or similar utilities which are present in each web service framework.
for example in jax-ws package (project Metro which is available at http://metro.dev.java.net)
you can create an static stub using following command:
This command will generate some java class which represent the above web service, you will only need to interact with this classes in order to invoke some services.
for more information about wsimport you may take a look at: http://java.sun.com/webservices/docs/2.0/jaxws/wsimport.html
[ February 27, 2008: Message edited by: Masoud Kalali ]