StormChart is a simple charting library written in C# for both ASP.NET 1.1 and .NET 2.0. It is written as a web user control. The charts are configured via an XML configuration file and the charts accept data via XML input files as well. These files can be generated on the fly by your software or just precreated and delivered to the control via a URL.
The library can render Line, Bar and 3D Pie charts.
It is open source, under the GNU Lesser Public Licence, so you are free to use this in open source or commercial applications.