Some WotLK info is making the rounds

Raids & Dungeons

• All raid dungeons in Wrath of the Lich King will have both 10-person and 25-person versions. So at level 80, every major encounter and every big boss fight can be experienced with a group of 10. (Gamespy.com)
  
• 25-person raiding progression is not dependent on 10-person raiding progression. (Gamespy.com)
  
• There will be no attunements or keys to obtain, and you won't be locked out of a 25-person instance if you decide to attempt the 10-person version, and vice-versa. (Gamespy.com)
  
• 25-person raids will earn more, higher-level rewards, in what should be the equivalent of one "tier" of loot quality. (Gamespy.com)
  
• A new instance focused on the different dragonflights "The Chamber of Aspects" might be added to the game, but this isn't confirmed yet. (Gamespy.com)
  
• Zero raid bosses have been designed at this point. (Gamespy.com)
  
  

Others

• Players will unlock their flying mount at level 77. (Gamespy.com)
  
• You can use your Outland flying mount, and new flying mounts will be available. (Gamespy.co