Some Useful tools

PDFTK:
The tools can be used to merge two or more PDF documents into a single PDF document. I found this really use. Here's the link to PDFTK

PS2PDF:
ps2pdf is a linux utility. I have cygwin installed on my windows system. The tools is pretty useful in converting a doc in ps format to PDF format. I found a very good article to generate PS file.. Once the PS file is generated, you can use ps2pdf to create the PDF files. :-)