<p>I can't seem to find much documentation on X-Sendfile or example code for PHP (there is some rails code).</p>

<p>Anyone used it before and would mind giving a quick snippet of code and a brief description?</p>

X-Sendfile is an HTTP header, so you want something like this:
```
```
header("X-Sendfile: $filename");
```
```
Your web server picks it up if correctly configured.  Here's some more details:
http://www.jasny.net/articles/how-i-php-x-sendfile/