In http://windows.php.net/downloads I couldn't find any x64 built for download. Further I have to choose among "Thread Safe" and "Non Thread Safe" with no explanation whether one is safer than the other or it performs better. The install.txt inside the available ZIPs for download seems out-dated an it doesn't mention anything about this.
In the installation manual found in the PHP site they don't say a word about it either...
Another doubt is once I know what to download (and why), should it be setup as a FastCGI module or as an ISAPI extension?
You could install the Microsoft Web Platform. Its just a couple of clicks and everything is configured correctly and ready to run!! It includes many web applications, frameworks, and samples, and it gives you the possibility to add anything that you want trough a selection. The url to download is www.asp.net/downloads pd: of course the PHP framework is included, hehehe don't get confused just because is from Microsoft.