A link to an example of GWT application: hucourse – a class viewer on googlecode.com.
I prefer Netbeans over Eclipse too. To develop for GWT, I used the following setup steps without installing gwt4nb plugin.
GWT client development can be done simply with the original NetBeans IDE, without the special GWT4NB add-on. The add-on is more for development involving the server side. As a client-only GWT tool, it improves the development productivity greatly.
GWT AJAX connects to third-party JSON web service avoiding the restriction of the same-origin-policy: a terminology is called JSONP.