If you're wondering what Obama did during his years as an Illinois legislator, The Weekly Standard has just published a lengthy piece by Stanley Kurtz on that topic. The article obviously covers domestic rather than foreign policy, but I've included it for its general interest.
In general, Obama supported affirmative action and set-asides, and based his strategy on the African-American vote. In this, he met with some opposition. In 1999, for example, he attacked the black caucus for not voting together to put a riverboat casino in a minority neighborhood. State Senator Mary Flowers responded: "The Black Caucus is from different tribes, different walks of life. I don't expect all of the whites to vote alike...Why is it that all of us should walk alike, talk alike, and vote alike? ... I was chosen by my constituents to represent them, and that is what I try to do." Sounds like she's the post-racial politician.
Anyway, there's plenty more, on crime and prison policy, social welfare legislation, etc.