Grigori mentions that the release date for Unity has been rescheduled for April 7, 2008 as opposed to the original March 15, 2008. There is a good chance that Enterprise Library 4.0 CTP 1 will be pushed back to April 7th as well, but Grigori didn't say one way or the other.
In the meantime, you can check out the Unity IoC Screencast :)