Hello ERGUN TEKER,
Automatically adding Silverlight controls to the toolbox is not well supported for VS2008 yet (I hope Microsoft improve that in the future). That is why our installer does not add controls to the toolbox.
To add them manually, right click your toolbox, select Choose Items... and pick the Telerik assemblies. Check
this help topic for details.
Sincerely yours,
Hristo Deshev
the Telerik team