1) To show and process your 'Desktop' data, you can use different binding methods implemented in RadTreeView control. Please review our online documentation (binding section) for details and choose one that is suitable for your application.
2) To learn how to setup and use Drag & Drop operation between RadTreeView controls, you can take a look at our Demo application, RadTreeView >> Drag & Drop section. In addition, you can read the Enable Drag and Drop article in our online documentation.
I hope this helps. Do not hesitate to contact us if you have further questions or issues.
the Telerik team
Q2’11 SP1 of RadControls for WinForms is available for download (see what's new); also available is the Q3'11 Roadmap for Telerik Windows Forms controls.