One of the coolest features in Silverlight 2.0 is deepzoom. I guess most of you have already seen the deepzoom demo with the hardrock café memorabilia: http://memorabilia.hardrock.com/
You can download the Deepzoom composer here, create you own compilation and export it to a *.bin file. A complete demo on how you can control this *.bin file from c# can be found on the blog of Dan Waters.
The tutorial includes a video and the complete source code.