We just uploaded a video produced by Sahil Malik, a Microsoft MVP and INETA speaker. This video shows how to use Telerik Silverlight controls in SharePoint 2010. The approach demonstrated in this video is Telerik Silverlight controls working with the client object model, in particular RadScheduler talking to the Calendar list.
For more details you can also check Sahil's blogpost at: Telerik Controls with SharePoint 2010 Client Object Model
Nikolay Atanasov is Product Manager in Telerik AppPrototyper Team