I work with a few clients that have a need to view a lot of data quickly in order to make decisions about their business. Many times a client will ask me to put together a report that lists something like Aged Receivables. Then they would like to be able to see what makes up those numbers and drill down on the information at hand.

The problem is that when you present the user with a vast amount of information in numeric form, the user has to interperet that information and paint a mental picture of what they mean.
I have found that in most cases, as the saying goes, a picture says a thousand words. For that reason, I prefer to paint the picture for the user right from the start.
Being somewhat of a spend-thrift, I am always looking for ways to either "do-it-myself" or to find a very inexpensive (hopefully free) control that I can use in my applications. This keeps my overhead down and I find that my clients seem to approve of my lower costs. That is why I was so excited to fin
WebChart a few years ago.
WebCharts is totally free and allows you to create some pretty nice charts and graphs. The control includes the following formats:
Line Charts
Smooth Line Charts
Column Charts
Area Charts
Scattered Charts
Stacked Column Charts
Pie Charts
Stacked Area Charts
The chart control will output in several image formats including JPG, GIF and PNG (the screenshots are PNG files - I hope they work in your browser!).

All of the documentation is on the website for the charts found at the link above. If you need to display data in a chart of some kind and you don't feel like buying one of the commercial charting software systems out there, I recommend checking out WebCharts.