Hello,
Are the controls visible in the Visual Studio toolbox? Do they become visible if you right-click the toolbox and select "Show All". If not, you can try adding them manually - right-click on the toolbox, select "Add Tab" and then right-click in the new tab and select "Choose Items...". Browse to the RadControls assemblies (Rad*.Net2.dll files) and select them in the Choose Items dialog.
If the controls are visible in the toolbox, but are grayed out, you will need to change the target framework of your project.
All the best,
Lini
the Telerik team