function seolulink($text){
    $tr = array('ş','Ş','ı','İ','ğ','Ğ','ü','Ü','ö','Ö','Ç','ç');
    $eng = array('s','S','i','I','g','G','u','U','o','O','C','c');
    $text = str_replace($tr,$eng,$text);
    $text = eregi_replace('[^0-9A-Za-z]',"-",$text);

    $text = preg_replace("@--*@","-",$text);
    return strtolower($text);
}  

$kelime = 'Ali Ata Bak';
echo seolulink($kelime);