As you may know SharePoint 2010 comes with considerably new theme support. Themes are now packaged using the Office Open XML format as .THMX files. THMX files are ZIP files that combine XML definitions for the theme styles, and image resources according to the standards.
For more detailed information about SP2010 Themes you can refer to:
Creating Document Themes with the Office Open XML Formats
If you are aiming to get a consistent visual appearance of SP2010 layout and Telerik's WebParts you can achieve it by creating custom skins /for the controls/ that have the same appearance and name as the Themes loaded in SP2010.
More information about how our skins work and creating custom skins can be found here:
How skins work
Creating a custom skin
Once having the custom skin you need to register it /load css files and images/ and set a skin name to the control. More about loading custom skins -> http://www.telerik.com/help/aspnet-ajax/skinregistration.html
So far, this is the mechanism for achieving visual style compatibility. Hope this helps!
All the best,
Vasil Yordanov, UX Team
the Telerik team
Check out Telerik Trainer
, the state of the art learning tool for Telerik products.