At the moment if you want to turn it into a desktop application then you've got two choices:
1. WPF application - copy / share the code with a full blown WPF application and fix any incompatibility errors (Silverlight is a subset of the full .NET framework so there shouldn't be many).
2. Mesh Application - Live Mesh applications include the ability to run Silverlight outside of the browser, like a desktop application (short cuts, start menu items etc). I've done a bit of a proof of concept of this (http://www.vimeo.com/2542327 for an overview) but this introduces a hard dependancy on the user having Live Mesh installed so for the moment it's just proof of concept.
do you run OS X? I guess you could just make a browser app (eg, Fluid)
I was just thinking users like having a "desktop" application - might re-iterate the lovely Silverlight experience if the user could "download" a copy.
Maybe, MAYBE, a little too many refelctions on the site. Just my 2 cents.
Can you turn this web app into a desktop app easily with silverlight?