Jon White, a Technology Specialist over on the CRM Online team, has been playing with custom dashboards and recently posted his work to the CRM Online blog. He walks through how he pulls the data using CRM SDK web services and uses LINQ to manipulate the data. Finally he uses the free Microsoft Chart Controls to paint some pretty pictures. Nice post, Jon.
Have a look at the blog post here: Microsoft Dynamics CRM Online Team Blog : CRM Online Custom Built Dashboards