The $5K buy-in for advanced publishing is now gone, and the Phase One (August 1st) and Phase Two (January 2009) go-live dates have now been eliminated, in favor of a single new date: October 1st.
The license and the System Reference Document will be available when the 4th Edition D&D rules are officially released in early June.
As it says in the announcement:
A small group of publishers received advanced notice and will receive these documents prior to June 6, at no cost, in order to prepare for publication of compatible materials by the effective start date.
I will confirm here that Adamant Entertainment is one of those publishers who have received advanced notice.
I will not be making any announcements regarding our plans for 4th Edition until such time as I have actually seen the Game System License, and can thereby determine if the terms of the license are acceptable, and the sort of products we wish to produce are allowed.