Some general comment and information about PDF - http://www.codinghorror.com/blog/archives/001028.html

http://blog.taragana.com/index.php/archive/how-to-5-extremely-easy-ways-to-convert-a-word-document-to-a-pdf-file/

http://www.ubuntugeek.com/list-of-pdf-editing-tools-for-ubuntu.html