POINTS.
We just did it on one of our web servers. It's running windows 2003 standard server and it's only role is a web server.
PHP installed perfectly fine and setup all the .php extentions to the executable on the server for every site. Only thing I had to do was add in index.php as a default page.
Installing MySQL on that same server today.
Although, I highly prefer a *nix box for PHP/MySQL applications.
Why would you not want SQL?
MySql doesn't go well with .asp.
To the OP:
Any specific reason you need .asp? You can run both, can usually get IIS servers which run with php now.