PDFtk - PDFtk is a simple tool for doing everyday things with PDF documents.
PDF Joiner - This online tool allows you to join several PDF documents into a single file, free of charge.
AutoMetadata - AutoMetadata is a tool for exploring and manipulating metadata, document properties, and viewer preferences in multiple PDF documents.
PDFChef Merge PDF - PDFChef Merge PDF is an online tool that allows you to merge multiple PDf files into one quickly and securely.
Edit PDF metadata - Edit PDF metadata is an online tool from PDFCandy that can manipulate PDF info and metadata.
PDFill - Open, View, Edit, Save and Print PDF Documents without Adobe Acrobat