Before starting this tutorial entry its worth mentioning a few people who have helped my along the one. Firstly a member of the GWT Group named AdamT who helped clear up a lot of things when implementing Cross Site JSONP calls. We had a discussion on the GWT group:
Group Link
Secondly Dan Morill of Google who has wrote a very descriptive article on how to achieve this and much of this tutorial is based around his article.
Dans Article
And finally my boss Chris who after I implemented...
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