You can use the PHP class that is available here :
http://www.pdftotext.eu
This is a public domain PDF text extractor entirely written in pure PHP, meaning that you do not need to rely on external commands. It provides a simple interface to retrieve text :
include ( 'PdfToText.phpclass' ) ;
$pdf = new PdfToText ( 'mysample.pdf' ) ;
echo "PDF contents are : " . $pdf -> Text . "\n" ;