How ASP.NET AJAX (and RadAjax in particular) works you can learn from the series of articles
on this subject you can find on our blogs. The same concepts are applicable in SharePoint environment.
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