Hi,
Currently for development Windows tablet and phone applications your options are:
Tablet: ArcGIS Runtime SDK for WPF
Phone: ArcGIS Runtime SDK for Windows Phone
The WPF SDK can be used to build disconnected editing workflows based on File Geodatabases, but if you editing scenario requires integrating edits back into your enterprise geodatabase it is advisable to wait for the forthcoming ArcGIS Runtime SDK for .NET which supports development of apps for the Desktop, Store and Phone environments. The .NET SDK includes the new ArcGIS Runtime offline editing and synchronization capabilities.
This new SDK will soon be made available as a beta with the initial full release planned for early summer 2014. Typically beta software does not provide you with a go-live license, therefore you can undertake your development with the beta version but will need to wait until the actual release in order to deploy.
If you've started any development with the existing WPF SDK there are a few tips for migration on this thread: http://forums.arcgis.com/threads/88329-The-history-and-future-of-the-ArcGIS-SDKs-for-.NET.
Cheers
Mike