Hi,
Here a nice article about reporting in infopath :
http://msdn.microsoft.com/msdnmag/issues/05/03/InsideMSDN/
it use "Microsoft Office Chart".
there is another way, try create a graph report on .html/.aspx/.php pages and show it on task pane, I never try, but I think it will work.
here some article :
http://msdn.microsoft.com/msdnmag/issues/03/07/ScalableVectorGraphics/
http://msdn.microsoft.com/msdnmag/issues/02/02/ASPDraw/
erwin.