Wondering about using GWT on a big project? Curious whether Google's eating it's own dog food? Well look no further than Google Health.  

A quick 'view source' of the just launched Google Health site will show some code that should be very familiar to GWT developers.

<script language="javascript"
<iframe id="__gwt_historyFrame" src="javascript:''" style="width:0;height:0;border:0;overflow:auto"></iframe>

Get kick-started with your own GWT app with 15,000 lines of GWT source and my book Web 2.0 Application Development with GWT which will show you how integrate GWT with Spring MVC, Hibernate and Spring Security and a host of other Java technologies.