A. Microsoft have released the first NT Option Pack QFE (Quick Fix Engineering) Update but this actually only updates IIS 4.0 at this time.
The update includes every hotfix made to IIS from its release. This is a cumulative hotfix and you should only install this if you are experiencing specific problems with IIS. The new intent is about every month or so or when appropriate release a new fix pack. The value add here is not waiting for such a long period of time between service packs. Customers who are experiencing problems don't need to hunt down individual hotfixes any more they just download this update and get everything.
The uninstall is very clean, so if something goes wrong, remove the fix. Something new here is in letting customers know what DLL's are being replaced up front. Upon installation of the update, the file iis_hotfix.htm is dropped in the users \inetsrv directory. This file will contain all of the information about the fix and should make it very easy for PSS to determine what version of IIS the customer is using.