Looking at this post again...
Mart's approach works for .doc files viewed from the web if your file associations are set to view from web or prompt to view/save instead of automatically saving it.
If you don't have word on your machine, and want to view local files, you'd also install the viewer and make sure your file assocations for .doc files are set to your browser. I think this is done automatically if you install the viewer without having word installed, but I don't know for sure.
File associations are set in My Computer|Options|Folder Options|File Types