Zend FR

        foreach ($mesPages as $Page) { // Pour chaque page
            $pdf->pages[] = ($page = $pdf->newPage($format["format"]));
            $page->setStyle($style);
            $y=$format["hauteur"]-$format["marge_t"];
            foreach ($Page as $Ligne) { // Pour chaque ligne
                if(strpos($Ligne,chr(0x0d))) { // Je regarde s'il y a une superposition
                    $maLigne=explode(chr(0x0d),$Ligne); // Si oui je mets dans un array
                    foreach ($maLigne as $superpos) { // Pour chaque ligne superposée
                        $page->drawText($superpos, $format["marge_l"], $y);
                    }
                } else {
                        $page->drawText($Ligne, $format["marge_l"], $y);
                }
                $y-=$format["ligne"];
            }
        $i++;
        if ($i==$nbrpage) break;
        }

protected function getWrappedText($string, Zend_Pdf_Style $style,$max_width)
{
    $wrappedText = '' ;
    $lines = explode("\n",$string) ;
    foreach($lines as $line) {
         $words = explode(' ',$line) ;
         $word_count = count($words) ;
         $i = 0 ;
         $wrappedLine = '' ;
         while($i < $word_count)
         {
             /* if adding a new word isn't wider than $max_width,
             we add the word */
             if($this->widthForStringUsingFontSize($wrappedLine.' '.$words[$i]
                 ,$style->getFont()
                 , $style->getFontSize()) < $max_width) {
                 if(!empty($wrappedLine)) {
                     $wrappedLine .= ' ' ;
                 }
                 $wrappedLine .= $words[$i] ;
             } else {
                 $wrappedText .= $wrappedLine."\n" ;
                 $wrappedLine = $words[$i] ;
             }
             $i++ ;
         }
         $wrappedText .= $wrappedLine."\n" ;
     }
     return $wrappedText ;
}

/**
 * found here, not sure of the author :
 * http://devzone.zend.com/article/2525-Zend_Pdf-tutorial#comments-2535
 */
 protected function widthForStringUsingFontSize($string, $font, $fontSize)
 {
     $drawingString = iconv('UTF-8', 'UTF-16BE//IGNORE', $string);
     $characters = array();
     for ($i = 0; $i < strlen($drawingString); $i++) {
         $characters[] = (ord($drawingString[$i++]) << 8 ) | ord($drawingString[$i]);
     }
     $glyphs = $font->glyphNumbersForCharacters($characters);
     $widths = $font->widthsForGlyphs($glyphs);
     $stringWidth = (array_sum($widths) / $font->getUnitsPerEm()) * $fontSize;
     return $stringWidth;
 }

then you can draw the text easily :

$y = 700;
$lines = explode("\n",$this->getWrappedText($text,$style_text,400)) ;
foreach($lines as $line)
{
    $page2->drawText($line, 140, $y);
    $y-=15;
}