I’ve updated the sample I started here by implementing Create Update and Delete methods. The library is still not complete or well tested, but it is at least a head start to building a CRUD capable Windows 8 Metro style application using the CRM 2011 OData (aka Organization Data) service. Both the helper web resource and the Windows 8 Metro style source code have been updated. The Visual Studio solution now has a little sample Metro style app to quickly test out the functionality of the library.
To get the sample to work, you will need to import the updated CRM solution package which updates the helper web resource. Also, make sure you change the CRM organization url in the sample app. You can still follow the instructions from the first post since there are no breaking changes in the sample, just new functionality.