Estrich writes that while Obama "is an inspirational and impressive guy, he has yet to make the five policy speeches that would give substance to his agenda."
Haven't we killed the "Obama has no substance" meme yet? And why five? Since she asked, here's the full set of Obama speeches, policy and otherwise. Policy-wise, here are speeches on 1) economic policy, 2) another on economic policy 3) foreign policy , 4) education, 5) Iraq, 6) energy, 7) the military, 8) urban poverty, and 9) health care.
Reading speeches is actually a pretty inefficient way to figure out a candidate's positions. If you're hungry for policy nitty-gritty, check out the 64-page Blueprint for Change at Obama's website.