What the heck for?
The ONLY thing that IIS does with timezone is pretty much using it to determine how to writet he log file, IF you wan them no to be written in UTC anyway, which is highly recommended.
Anything else is not IIS running a timezone, but your application relying on some user settings, which is bad style to start with. All presentation should not use a server side info, but a user specific setting for handling presentation, or hardcode timezone information.
I totally miss to understand what the question is here - pertty much a web application should not have a concept of a local user timezone to start with, programming wise.