While searching and reading article on the internet regarding silverlight I have found interested article which give the linke to the white paper regarding the Difference between silverlight and WPF. Wintellect, in collaboration with Microsoft, has released a whitepaper at CodePlex that fully explains the differences between these two technologies. You can get the latest version from the CodePlex site.
You can also download the version 1.1 from here which has the release date of Fri Jul 17 2009.
All and any comments / bugs / suggestions are welcomed !