Considering the ping ponging that has been going on between the Big Three, Iran, and the IAEA, I would say that this declaration by Iran represents progress but not much more than that. To an extent we are in agreement as to how much the Iranians can be trusted, but differ in how this crisis shoul be approached. Kerry suggested in the first debate that he would engage in bilateral talks with Iran and North Korea, which is in stark contrast to how the Bush Administration has been handling theses two crises all along.
If you, like I do, have issuses with the Iranian intentions, why engage in bilateral talks/ agreements? Wouldn't making them responsible to other nations better serve our interests?