We would suggest you to check our Silverlight charting
controls that you can easily integrate into your ASP.NET applications as demonstrated in this online example here
. You can find more information on integrating our Silverlight controls in ASP.NET here
At the moment we do not have any immediate plans on developing GDI+ based version of RadGauge for ASP.NET and we have not planned any major improvements for the ASP.NET charting control for Q2 2009 either. As for the next release -- there is a service pack release scheduled for the beginning of June, and the Q2 release should be out in the beginning of July.
the Telerik team