For GWT starters

download GWT from http://google-web-toolkit.googlecode.com/files/gwt-2.2.0.zip and create ur first app.

http://code.google.com/webtoolkit/doc/latest/tutorial/gettingstarted.html

U can also see how the application looks after completion.U dnt need anything except compatibke browser and internet to view following examples.

http://gwt.google.com/samples/Showcase/Showcase.html

http://gwt.google.com/samples/Mail/Mail.html

http://gwt.google.com/samples/DynaTable/DynaTable.html

http://sticky.appspot.com/

http://code.google.com/webtoolkit/examples/