I took a reasonable resolution version of the Silverlight 2 Developer Reference Poster and crossed that with the Deep Zoom Composer, added a JS mouse wheel library and in about 5 minutes had a Deep Zoom version of the poster running in Silverlight. The sample is posted here.
The XAML is simple – just point the MultiScaleImage element to the output of the Deep Zoom Composer.
<Grid x:Name="LayoutRoot" Background="White">
<MultiScaleImage x:Name="img" Source="poster/info.bin"/>