Issue: You want to add a WCF service reference to a Windows Phone 7 project in Visual Studio 2010 RC Ultimate. You right click the project to find “Add Service Reference…” option is not available.
Solution: Assume this will be fixed in the RTM. Until then open up your Windows Phone 7 project in the Visual Studio 2010 Express edition that was installed with the Windows Phone Developer Tools. The express allows you to “Add Service Reference…” to the WP7 project without issue. Once done, reload your project in VS 2010 RC Ulitimate.