Handy little function that returns the number of files (not directories) that exists under a directory. 
Choose if you want the function to recurse through sub-directories with the second parameter - 
the default mode (false) is just to count the files directly under the supplied path.

<?php

  /**
   * Return the number of files that resides under a directory.
   * 
   * @return integer
   * @param    string (required)   The directory you want to start in
   * @param    boolean (optional)  Recursive counting. Default to FALSE. 
   * @param    integer (optional)  Initial value of file count
   */  

  function num_files($dir, $recursive=false, $counter=0) {
    static $counter;
    if(is_dir($dir)) {
      if($dh = opendir($dir)) {
        while(($file = readdir($dh)) !== false) {
          if($file != "." && $file != "..") {
              $counter = (is_dir($dir."/".$file)) ? num_files($dir."/".$file, $recursive, $counter) : $counter+1;
          }
        }
        closedir($dh);
      }
    }
    return $counter;
  }

  // Usage:
  $nfiles = num_files("/home/kchr", true); // count all files that resides under /home/kchr, including subdirs
  $nfiles = num_files("/tmp"); // count the files directly under /tmp

?>