The Silverlight 5 is on its way, so we do not support Silverlight 3 anymore. I can suggest you for now to check out our Silverlight 4 online demos here
and let us know if you have any concerns about our controls.
the Telerik team
Do you want to have your say when we set our development plans? Do you want to know when a feature you care about is added or when a bug fixed? Explore the Telerik Public Issue Tracking
system and vote to affect the priority of the items