What version of Java are you running? That is going to affect which web services toolkit you can use.
Look at this post for a quick summary of the more popular SOAP web services toolkits. Most of these toolkits already come with some sample applications.
Leave Eclipse out of it for now - you'll learn more (post).
While you are in that topic have a look at this post.
If you are interested in web services in a Java enterprise setting then you may find this topic useful. While most of the posts relate to J2EE 1.4 (with the older JAX-RPC 1.1) there are a few links that relate to Java EE 5 (with the more up-to-date JAX-WS 2.0).