I have a Silverlight 3.0 application that is using a WCF service to communicate with the database, and when I have large amounts of data being returned from the service meth
Change the maxItemsInObjectGraph in your WCF service for each endpoint, changing it in Silverlight means the client will be able to support the behavior, but the service must support it aswell.
After changing it in your service, regenerate the proxy/update web service, and you will get a new ServiceReference.config, that will include the new maxItemsInObjectGraph value