Feb 12, 2010
Microsoft at Visual Studio presentation last week, they said it will be Apr 12.
But, Lab Management VS2010 product will not be included in the Apr 12 release, rather the Lab Management will go into Beta 3.
Feb 10, 2010
I read a rumor that it would be a couple of weeks after the .NET 4 release which is scheduled for March 22. So it should be sometime in early April.