I used to use Visual Studio to develop and debug PHP modules with Phalanger, a compiler for .NET which also has a Visual Studio integration add-on. Please see
http://en.wikipedia.org/wiki/Phalanger_%28compiler%29[
^],
http://www.php-compiler.net/[
^].
Unfortunately the programming model of ASP.NET with Phalanger is very different from "standard" PHP modules from Web servers. So, I used only a a sub-set of PHP valid for its "standard" use. It was enough for development and debugging. It helped a lot.
—SA