Wizards announced today that the updated character builder tool was released. I had posted previously (here) that the update was to have been released a week ago, but apparently Wizards found a serious printing problem and opted to hold it back for another week. The Wizards formal release announcement can be read here.
If you read the announcement the really big news is that the new on-line Monster Tool is scheduled to be released March 22. I must admit I haven't thought much about "Essentials Monsters" versus "Core DnD Monsters" ... I going to go with the assumption (always dangerous, I know) that the tool will allow to you select from either category. The Monster Tool has been beta tested for the last three months so hopefully it should be pretty solid upon release.