Firefox provides a very nice add-on Print pages to Pdf to convert Web pages straight to PDF files.
This add-on is quite special as it is not using any online service for the conversion job.
It is using wkhtmltopdf library which convert html to pdf using the webkit rendering engine.
This Firefox add-on works Out Of The Box under any Ubuntu i386 distribution.
It was broken under Ubuntu Amd64 for version 0.1.8.5, but has been corrected on version 0.1.9.0.
This article explains how to solve this issue and to get a fully working one click solution to convert any HTML web page to a PDF document on a Ubuntu 64 computer.
It has been tested under Ubuntu Amd64 12.04 LTS, with Firefox 20 and Print pages to Pdf 0.1.9.0.