I have deployed a Silverlight 2 application which uses ADO.NET Dataservices to a IIS 6.
Problem #1: you see nothing in Browser
register MIME Type in IIS and restart IIS
Problem #2: no data is sown in Silverlight
In my case it was a 2nd hostheader entry in the Web site. Remove the 2nd hostheader, restart the service and call the ADO.NET Dataservice (svc) directly in Browser