Here is information about the changes from Victoria Strauss of Writer Beware, including a pdf of the actual announcement from Random House. The announcement is also up here.
The short version: The imprints will now offer writers a choice of publishing models, and in the profit-sharing version of the model, some significant changes have been made.
I’ll be looking at the revisions and be offering my personal thoughts at some point in the reasonably near future.
Likewise I know the SFWA board has been made aware of these changes, although I can’t give a timetable for a response there, if any.
Update: My additional immediate thoughts are here.