Microsoft recently released a cool new ASP.NET server control - <asp:chart /> - that can be used for free with ASP.NET 3.5 to enable rich browser-based charting scenarios.

Once installed the <asp:chart/> control shows up under the "Data" tab on the Toolbox, and can be easily declared on any ASP.NET page as a standard server control.
<asp:chart /> supports a rich assortment of chart options - including pie, area, range, point, circular, accumulation, data distribution, ajax interactive, doughnut, and more.  You can statically declare chart data within the control declaration, or alternatively use data-binding to populate it dynamically.  At runtime the server control generates an image (for example a .PNG file) that is referenced from the client HTML of the page using a <img/> element output by the <asp:chart/> control.  The server control supports the ability to cache the chart image, as well as save it on disk for persistent scenarios.  It does not require any other server software to be installed, and will work with any standard ASP.NET page. 

http://weblogs.asp.net/scottgu/archive/200...er-quot-gt.aspx