Silverlight / WPF - Wants to develop end user report designer tool using .Net technologies

Hi

   My client wants a reporting tool, where his end users can develop add hoc reports/ design document on run time
   please help with the approach

Thanks
Vijay T

doesn't sql server reporting services offer something like this?

Thanks for reply,

    actually have not worked on SSRS thing, can you provide me, any link on this so that i can move ahead.

Vijay T.