This is the Google GWT main tutorial, called stockWatcher you can find it here : http://code.google.com/webtoolkit/doc/1.6/tutorial/create.html

Added items : Real Time (20 minutes delayed actually) Yahoo finance Data, to have live quotes. Designed with GWT Designer More to come but will start it in another project. You can try the live app at http://sk-stockwatcher.appspot.com