limit number of characters

[error_22]

I want to limit the numbers of characters, but i dont know how to do that. Can someone help me?

PHP Code:

if ($show == "ad"){
    $sql = "SELECT * FROM ads Where id='".$_GET[id]."'";
    $result = mysql_query($sql) or die("SQL: $sql ".mysql_error());
    while ($adsresult = mysql_fetch_array($result, MYSQL_ASSOC))
    {
    echo "$adsresult[fname] $adsresult[lname] <br>
      <b>E-post:</b> $adsresult[email] <br>
      <b>Kategori:</b> $adsresult[category] <br>
      <b>Rubrik:</b> $adsresult[head] <br>
      <b>Meddelande:</b> $adsresult[message] <br>
      <b>Datum:</b> $adsresult[date] <br>";
  }} 


I want to limit the numbers of characters in just "$adsresult[message]" and also add "..." after, is that possible?

Thanks in advance
Niklas