The extension you need to uncomment in php.ini is
extension=php_mssql70.dll
this enables connection to mssql6.5 and 7.0
you also need to put in the .php file type in the Home Directory/Application Settings/Configuration in IIS.
I used the default
c:\php\php.exe %s %s
I have used php in NT to send mail and query mssql db's.