Weblabor

$m = preg_match_all('/http:\/\/[a-z0-9A-Z.]+(?(?=[\/])(.*))/', $message, $match); 

if ($m) { 
    $links = $match[0]; 
    for ($i=0; $i<$m; $i++) { 
        $message = str_replace($links[$i],'<a href="'.$links[$i].'">'.$links[$i].'</a>',$message); 
    } 
}

<?php
$a = array(
  'message' => ":) :D :(2 :( :P, http://weblabor.hu/",
);
$message = strtr($a['message'], array(
  "<" => "&lt;",
  ">" => "&gt;",
  ":D" => "<img src='smiley/sm01.gif' alt='sm01' />",
  ":P" => "<img src='smiley/sm02.gif' alt='sm02' />",
  ":(2" => "<img src='smiley/sm03.gif' alt='sm03' />",
  "[sm04]" => "<img src='smiley/sm04.gif' alt='sm04' />",
  ":(" => "<img src='smiley/sm05.gif' alt='sm05' />",
  ":)" => "<img src='smiley/sm06.gif' alt='sm06' />",
  "[smiley_dj]" => "<img src='smiley/sm07.gif' alt='sm07' />",
  "[smiley_drink]" => "<img src='smiley/sm08.gif' alt='sm08' />",
  "[smiley_Good_night]" => "<img src='smiley/sm09.gif' alt='sm09' />",
  "[smiley_Love]" => "<img src='smiley/sm10.gif' alt='sm10' />",
  "[smiley_Hello]" => "<img src='smiley/sm11.gif' alt='sm10' />",
));
$message = preg_replace("/
      (^|\s)                                                  # At the begining or after whitespace
      ((?:https?):\/\/                                        # Look for http or https schemes
      (?:                                                     # Userinfo (optional) which is typically
        (?:(?:[\w\.\-\+!$&'\(\)*\+,;=]|%[0-9a-f]{2})+:)*      # a username or a username and password
        (?:[\w\.\-\+%!$&'\(\)*\+,;=]|%[0-9a-f]{2})+@          # combination
      )?
      (?:
        (?:[a-z0-9\-\.]|%[0-9a-f]{2})+                        # A domain name or a IPv4 address
        |(?:\[(?:[0-9a-f]{0,4}:)*(?:[0-9a-f]{0,4})\])         # or a well formed IPv6 address
      )
      (?::[0-9]+)?                                            # Server port number (optional)
      (?:[\/|\?]
        (?:[\w#!:\.\?\+=&@$'~*,;\/\(\)\[\]\-]|%[0-9a-f]{2})   # The path and query (optional)
      *))
      ($|\s)                                                  # At the end or after whitespace
    /xi", '$1<a href="$2">$2</a>$3', $message);
echo $message, "\n";
?>