DotNetNuke has partnered with Telerik to make many of Telerik's ASP.NET AJAX controls available for use in DotNetNuke. The Telerik DLL that contains all the controls is included in all the latest versions of DotNetNuke. The DotNetNuke Corporation has provided a large set of wrappers for many of Telerik's controls to make them easy to include in DotNetNuke modules and skins.

Everyone is free to use any of the wrappers for skin and module development. To use a Telerik control directly however, Module Developers will need to purchase a license from Telerik or purchase the DotNetNuke Professional Edition (or greater).

Most of the wrappers can be found in this namespace: DotNetNuke.Web.UI.WebControls

There are also a variety of SkinObjects available through CodePlex that provide extended capabilities:
RadTabStrip
RadMenu
RadPanelBar
RadTreeView
RadRotator

For license Information and details about the partnership, please reference this link:
Telerik DNN Partnership Q&A


For additional information, please reference this forum thread:

Using the DotNetNuke wrappers for Telerik Controls

List of wrappers

All the Telerik RadControls are included with every DotNetNuke distribution and any developer working on core components may make use of any Telerik control.

The core also includes wrapper controls for several Telerik RadControls which third party developers can use to take advantage of those particular controls in their own modules. At present, the following wrapper controls exist:

Telerik wrappers

DNN Wrapper Control	Wrapped Telerik RadControl
DnnComboBox	RadComboBox
DnnGrid	RadGrid
DnnGridBoundColumn	GridBoundColumn
DnnGridCheckBoxColumn	GridCheckBoxColumn
DnnGridCheckBoxColumn	GridCheckBoxColumn
DnnGridClientSelectColumn	GridClientSelectColumn
DnnGridEditColumn	GridEditColumn
DnnGridHyperLinkColumn	GridHyperLinkColumn
DnnGridImageColumn	GridImageColumn
DnnGridTableView	GridTableView
DnnGridTemplateColumn	GridTemplateColumn
DnnListBox	RadListBox
DnnMultiPage	RadMultiPage
DnnProgressArea	RadProgressArea
DnnProgressManager	RadProgressManager
DnnTabStrip	RadTabStrip
DnnTextBox	RadTextBox
DnnToolTipManager	RadToolTipManager
DnnTreeView	RadTreeView
DnnWindowManager	RadWindowManager