installation instructions are inside the downloaded zip of php
This section has details about PHP download locations, and OS issues.
You can download PHP from any of the members of the PHP network of sites. These can be found at » http://www.php.net/. You can also use anonymous Git to get the absolute latest version of the source. For more information, go to » http://www.php.net/git.php.
We only distribute precompiled binaries for Windows systems, as we are not able to compile PHP for every major Linux/Unix platform with every extension combination. Also note, that many Linux distributions come with PHP built in these days. Windows binaries can be downloaded from our » Downloads page, for Linux binaries, please visit your distribution's website.
Note: Those marked with a * are to the best of our knowledge not thread safe; they are not recommended for use in a multi-threaded environment.
You will need to follow instructions provided with the library. Some of these libraries are detected automatically when you run the 'configure' script of PHP (such as the GD library), and others you will have to enable using '--with-EXTENSION' options to 'configure'. Run 'configure --help' for a listing of these.
See the PHP Wiki for the latest instructions: » Step by Step Build Instructions
You can find a browscap.ini file at » http://browscap.org/.
Thread Safety means that binary can work in a multithreaded webserver context, such as Apache 2 on Windows. Thread Safety works by creating a local storage copy in each thread, so that the data won't collide with another thread.
So what do I choose? If you choose to run PHP as a CGI binary, then you won't need thread safety, because the binary is invoked at each request. For multithreaded webservers, such as IIS5 and IIS6, you should use the threaded version of PHP.