Penguin agrees to give up price controls on ebooks for the next couple years, and they have to cancel existing contracts. The publisher will also be under strict scrutiny by the DOJ, a move which is clearly intended to prevent recidivism. Penguin will also be forbidden from agreeing to any kind of most favored nation (MFN) agreement that could undermine the effectiveness of the settlement, and that last bit will go on for 5 years..
Now that Penguin has settled we're down to only 2 defendants in what is becoming an elaborate game of chicken. The trial is set to start in June of 2013, so we have another 6 months to see if the two remaining defendants, Apple and Macmillan, decide to settle.
I'm betting that they will settle. After all, all of the Price Fix 6 except Penguin have already signed on to a settlement in Europe, so clearly they are not opposed to the idea.
The only reason we have not yet heard about the last 2 holdouts settling with the DOJ is probably because they're working out the nitty-gritty details, not because they want to go to trial.
I predict all the settlements will be announced by March 2013.