If you need a boost in GWT knowledge, check out these courses:
I am going to teach a Getting started with the Google Web Toolkit course. It is a two day course, aimed at GWT beginners. The course will take place at The Skills Matter eXchange - London, on April 18th and 19th 2011.
If you already know GWT basics, have a look at Dmitry Buzdin's Advanced Google Web Toolkit: Large-Scale GWT Development. This course takes place in late June.
In case you are unsure whether to attend a course or not, we do also offer a free event in April. Come to the In the Brain session Whats new in GWT 2.X on April 19th, 18:30PM at The Skills Matter eXchange.