Yes, you can implement drag and drop operations between GridViews in Silverlight as well and the approach is the same as in WPF.
I attached a sample project to illustrate how to implement such a scenario. Take a look at it and let me know if it works for you.
You can also implement drag and drop inside one GridView. More information about this scenario you can find here
Give it a try and let us know if you need more info.
the Telerik team
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