Got the news that the migration tool has been updated 5 days ago by the ADO.NET team.
You can get the package from NuGet using the command Install-Package EntityFramework.Migrations or Update-Package EntityFramework.Migrations if you have Alpha 3 installed. Going forward the migration tool will be RTM’ed as part of Entity Framework 4.3.
For someone coming from Alpha, I see a few changes
1. Settings.cs inside Migration folder has been replaced with Configuration.cs. You have to delete the old Settings.ca file
2. ChangeColumn API is now called AlterColumn