I'm looking into WCF and woud like to created my framework in a RESTful way. I've just started looking into ADO.NET Data Services, but it seems it only supports SQL Server, is this correct? Can you run in against Oracle?
ADO.net Data Services and WCF both feed off a model. You can provide restful access to your data using a proper model layer that accommodates Oracle driver. Things might not work out of the box. In WCF you can use an Oracle friendly mapper like NHibernate and expose your datacontracts in a restful way. For Astoria you might need to hunt for a EF provider for Oracle db. But its possible.
EDIT: It seems ADO.net Entity Framework is already Oracle friendly ! You have no problems going pure WCF or Astoria way
ADO.NET Data Services relies on the ADO.NET Entity Framework, and that definitely also supports Oracle. WCF in itself is totally database-agnostic - no limitations here. I don't see why you shouldn't be able to use ADO.NET Data Services with an Oracle backend.
Marc