Apple has finally updated their .Mac Webmail interface:
Introducing the next generation of webmail. With its smart use of the latest web technology, the new .Mac webmail will remind you of the Mail application on your desktop. You'll feel right at home with its simple and elegant interface, drag-and-drop capability, built in Address Book, and more
A sneak peak of the updated .Mac Webmail was originally posted in September.
The new .Mac Webmail provides a similar look and feel to Mac OS X's Mail application, and utilizes the latest web technologies to provide a more seamless experience. .Mac is a pay service provided by Apple. The basic package starts at $99.95 (US) per year for 1GB of .Mac Mail and iDisk storage.