WMP 11 has been on the news for XP, is a reluctance to disclose the names of the Microsoft employees issued, Microsoft in May 17 had issued a public version of RTM forthcoming release later this year, the fastest on the 14th next month.
Following is the updated list and RTM WMP before the improvements :

Features in WMP 11 for XP (June 06) :
* New UI
* Support for better synchronization for portable devices
* Album "stacks" of album art
* Indexed libraries with search-as-you-type 3-6
* User controlled downgrade of quality for DRM content to allow for smaller files
* DRM content will contain metadata that shows what the user is allowed to do with the file
* Includes Microsoft and MTV 's Urge Shakespeare store

Features in WMP 11 for Vista (King 07) :
* Everything that is in the WMP 11 for XP
* Playing content (including DRM) on your PC from another PC or device
* Viewing content from the Vista Media Available on PCs or other digital devices, such as Tivo
* Playback of High Value video content
* shelf integration with Windows Media Player
* Content Indexer change notification to sync My Music and WMP library
* Fullscreen DVD playback enhancements
* DRM Transcode
* High quality video streaming over home networks
* Media foundation for playback