I maybe wrong, but most of the windows hosting should support PHP. I have a windows hosting, and I have Joomla! running on it perfectly. Your windows web hosting package would mostly support PHP/MYSQL, unless they've specified they don't. This is because PHP/MYSQL are readily available for windows.

Most of the ASP/ASP.NET scripts only run on web servers supporting them, which is on windows. Though projects like mono have come forward, but the inability to conveniently use them on linux servers, one of the most popular, is not a good fact. But PHP runs on both windows and linux systems, and thats the reason its so popular. And also, PHP is Open Source.

But I did manage to find one for ASP: http://forum.snitz.com/.