print to pdf when not connected to printer

Sometimes we come across a situation where we want to print a confirmation e.g. a train/flight ticket; but don't have a printer directly connected.
At those times we can directly print to a pdf; which we can print later.
cups-pdf is the package that does the trick and in Ubuntu it can be installed by "sudo aptitude install cups-pdf".For other rpm based distributions use "yum install cups-pdf".

More details can be found here :
http://ubuntu-tutorials.com/2008/07/03/printi-directly-to-pdf-in-ubuntu-804/