Assuming you're working with IIS 6 or greater, there are two
VBS scripts/utilities available that can help you here.
1) "IIsCnfg.vbs" - usually located at
%WINDDIR%system32\IIsCnfg.vbs
2) "adsutil.vbs" - usually located in Inetpub\AdminScripts
You should be able to search the web for documentation on
each of these VBS utilities pretty easily. Essentially, you can
export IIS configuration data from the IIS "metabase" into XML
format. You can then use that as a "template" for your site
configurations moving forward. Ideally, if there are only a few
values you need to search & replace, you can set up new IIS
configurations pretty rapidly, and load them via the command line
with these VBS utils.