HTTP Error 404.17 - PHP on IIS7 under 64bit Vista
If you're getting...
"HTTP Error 404.17 - Not Found - The requested content appears to be script and will not be served by the static file handler."
...on Vista while trying to get PHP working under IIS7 with the standard ISAPI "php5isapi.dll" ask yourself, are you running 64-bit? That ISAPI DLL is a 32-bit DLL, so you'll have to either change your default Application Pool to enable 32-bit, or preferably create a separate 32-bit AppPool for your PHP Application.
Right click on the Application Pool and select "Advanced Settings" then "Enable 32-bit Applications."
At this point, you're all set with the standard ISAPI PHP stuff.
Even better, consider using the FastCGI for IIS component. I'll do a screencast on that soon.