title: Where is System.Data.Linq
body: <p>I am writing a WP7 app and looking to use the Microsoft CE database available under Mango.  I have upgraded my VS10 environment and I am creating apps at version 7.1.</p>
  
  <p>When I go to include the references for the database side of things they are unavailable i.e.</p>
  
  <p>System.Data.Linq 
  System.Data.Linq.Mapping</p>
  
  <p>Do I need to install anything here or have I done something wrong. Where should I be looking for them?</p>