Software - PDF

PDF995 (Free & Recommended..lots of features)
www.pdf995.com

PDF Sharp - (Free .PDF merger), works well *
http://www.pdfsharp.com/

http://www.verypdf.com/

http://www.bluebeam.com/

http://en.pdf24.org/

http://www.get-pdf.com/new/

http://www.pdfill.com/