We're using Windows 2000, IIS5 and PHP4.0.4pl1. I'm sure it works the same under NT4, but not so sure from Apache. My guess is that it would because a lot of people are running Apache instead of IIS5.
All we did to get SQL Server 7 and SQL Server 2000 to work was turn on the module in the PHP.INI file. The line should read:
extension=php_mssql70.dll
We are really pleased with the ADODB library. It's available at http://php.weblogs.com/ADODB. You can access multiple databases by just changing a setting in your code. I highly recommend it. There are several modes for accessing SQL Server databases. We're using the setting for 'mssql'.
Mike