Get a SharePoint List GUID from the Browser
Go to the list settings page. Right click on "Title, description and navigation" and copy the URL. Paste that into notepad and copy everything after "List=" in the string. That's your URL Encoded GUID for the list. All you need to do is decode it. I found this php page that does it for you so you don't have to whip up a quick program to do it. I'm sure there are zillions of others around.
Or maybe there is a URL decoder somewhere in the MS stack that I'm not aware of. Anyone? Anyone?