It turns out the Windows BMP file format is similar to the Windows ICO file format.  Given that, it wasn't too hard for me to produce a Windows ICO/ICON decoder (parser) based on the work I did around a Silverlight BMP decoder.  I didn't spend a lot of time making the source efficient, so if you make improvements, let me know and I'll incorporate them into my version.  Click on the image below to run a live version of the Silverlight 3 based sample.

 

 ICON/ICO Decoder (Parser)