Oh, how I love free things. Especially free pretty things. And I'm the kind of person who things Flash charts and graphs are pretty, so I present amCharts and PHP/SWF Charts. amCharts is a relative newcomer that creates attractive Flash pie and donut charts based on data you put in a text file in either XML or CSV formats (which makes exporting from Excel easy). It's very configurable, allowing you to specify colors, border, tilt (for a 3D effect), labels, fonts, backgrounds, and so on. amCharts' creators promise bar, column, and line charts this spring.

PHP/SWF Charts is sort of amCharts' big brother. It's been around awhile longer and features more than a dozen different chart types and nearly unlimited configurability. As the name implies, PHP/SWF Charts uses PHP to load data from dynamic sources, but it's not required--there's XML/SWF Charts that will load data from a regular XML file. With its advanced features comes more complexity, of course, and the learning curve is probably greater, but if you need, say, a stacked 3D column chart, it's the way to go.

As I mentioned, both charting tools are free, but not totally free. The free version of amCharts will put a small link to amCharts.com in the corner of your charts, and PHP/SWF Charts will direct users to its web site if they click on it. For a single-site license amCharts will cost you 45 Euros (about US$60) and PHP/SWF charts will cost you US$45. "Enterprise" licenses for unlimited sites cost 245 Euros (~US$322) or $550 respectively.

Blogger and web designer Vitaly Friedman has put together a very handy list of nifty tools for drawing diagrams, charts and flow-charts. He identifies about 20 resources spanning free software, commercial software, web-based tools, and tutorials that will help you make pretty graphs, charts, and diagrams. Of course, I'm most interested in the free stuff, but if you use Illustrator or Excel, or are looking for something a little more robust, the tutorials and commercial tools could prove invaluable.