I think Barack has been pretty clear about his intentions on health care, economy, and the war.
There are also some amazing videos of his speeches out there that help you understand the kind of person Barack is. One of my favorites is a 30+ minute speech regarding religion, atheism, and how these issues are reflected in both the democratic and republican parties. If I had the link onhand I would give it to you, but it really paints his exact stance on separation of church and state, his personal beliefs, and where the constitution and our government fit in. This is a man that respects and understands the constitution, unlike those dirtbag fundamentalists.
The man is incredibly smart and tolerant, and displays a sensibility I've never seen in a politician. Some things that ALL of these candidates campaign on will be ambiguous however - like Hillary Clinton's supposed 'foreign experience' that has Bill's oldschool foreign advisors utterly confused, or John Mccain's "conservatism" that has the hardcore right wing shaking their heads.
I will tell you - I actually looked up Obama's legislation, voting records, and any kind of initiatives he was involved in, and I was impressed by what I saw. His record in US Senate is more impressive than Hillary's. I'm the most bitter and jaded person I know when it comes to anything political, and the fact that Obama has inspired and excited me about our political process continues to surprise and delight me.