When it’s about sharing documents you will find PDF as a godsend. The PDF files are the best 
format for exchanging and transferring documents because of the compact size, compatibility on any computers and mobile devices (mobile phone & E book reader) and the best of all- formatting of the original document remain preserved in the output PDF file.
There are a couple of reasons why you want to convert web pages to PDF format. Best advantage in my opinion – PDF format avoid clutter in managing files. When you save a single webpage locally to your computer you get two separate files ( .html file and a folder) and its very irritating to manage them when you’ve to save large number of webpages to you computer. Secondly, original content and format (including text, table and even embedded images) is presented by PDF on any system or device with no exceptions. This makes PDF files a universal file format for sharing documents .
There are plenty of options available to convert webpage to PDF online but i use two services which stands out of crowd by being aimed primarily at the quality of PDF documents.
WEb2PDF – This online webpage to PDF converter gives you nicely formatted PDF of the webpage that you can read on any device. The main advantage Web2PDF when compare to other tools is the quality of output file we get. The output PDF file preserved a webpage content completely. Another bonus point of this service is you can convert any webpage to PDF by sending email to [email protected]. And, then those Bookmarlets and extensions which make it very easy and fast to convert a webpage to PDF just by single click. The tool is often useful for webmasters and blogger, they can get and put JavaScript code/button on their website/blog so readers can download webpage as PDF for offline reading.
Joliprint – Joliprint is very handy tool which reformats blog posts and news articles in a very nifty printer friendly PDF file by removing the clutter around on a webpage – See example. Joliprint offers bookmarklet, plugins and a range of buttons for websites/blogs that turns a web page automatically into a PDF document. One feature that make Joliprint different from other tools – Joliprint bookmarlet can turn any Google Reader item and Read it Later lists items into PDF. Content of a webpage is presented with a readable two-column layout and with permalink of that webpage at the bottom. It eliminate distracting elements such as advertisements, frames etc. and makes reading webpages simpler than ever.
Also see- Highlight content on a Webpage then Download as PDF for Offline Reading