gistfile1.php

/**
 * Twitter message String
 * Searches in a string for links, replies, and hash and generates a <a>-Tag for the results.
 * @param {String} message
 * @return {String}
 */
function generateLinks ($message) {
  $pattern[0] = '/(http:\/\/[0-9a-z-_.\/]+)/i'; # find is urls
  $pattern[1] = '/@([0-9a-z-_]+)/'; # find is replies
  $pattern[2] = '/#([0-9a-z-_]+)/'; # find is hashes

  $replace[0] = '<a href="$1" title="external">$1</a>';
  $replace[1] = '<a href="http://www.twitter.com/$1">@$1</a>';
  $replace[2] = '<a href="http://search.twitter.com/search?q=$1">#$1</a>';

  return preg_replace($pattern, $replace, $message);
}