Nick,
You'll have to extract the icon out of the exe or dll for those programs. This is pretty easy with the resource editor from Visual Studio. Otherwise you might mine the internet looking for the icons or another resource extractor program.
>I am using ctTree from dbi-tech. I need to load images to imagelist for my tree. I can't seem to get to the icon for word, excel and pdf files. how do I get the icon or image file for these products? When I click on properties I see the icons, but where is the physical icon files?