http://sourceforge.net/projects/tcpdf/
TCPDF is an improved version of FPDF, the free PHP class to generate PDF files. TCPDF offers a bunch of new features, etc.
http://www.fpdf.org/
FPDF is a PHP class which allows to generate PDF files with pure PHP, that is to say without using the PDFlib library. F from FPDF stands for Free: you may use it for any kind of usage and modify it to suit your needs.
