Merge PDF files

Traditionally to merge to PDF files together you'd need to use Adobe Acrobat (not Reader). However, there are now many other options available and some are even free of charge. I found a very good one that's easy to use and fast. It's an online service but you do not have to sign in or give your e-mail address. Here it is:

PDF Merge
http://www.pdfmerge.com/


Update: January 2014
Here's another website that works really well too:
http://merge.smallpdf.com/   (thanks to Mathis Buchi for recommending this site)

In fact, try http://smallpdf.com/, there are a number of functions here such as compressing a PDF and creating a PDF from image files, etc.

Update: January 2015
PDFtk Free is a nice little Windows program that can merge PDF files, best if you don't want to upload your files to the web:
https://www.pdflabs.com/tools/pdftk-the-pdf-toolkit/