c/o Brian Suda:
"One of the most common questions I get asked is how to get started with data visualisations. Beyond following blogs, you need to practise – and to practise, you need to understand the tools available. In this article, I want to introduce you to 20 different tools for creating visualisations: from simple charts to complex graphs, maps and infographics. Almost everything here is available for free, and some you have probably installed already"
from source: http://www.netmagazine.com/