The March 20, 2008 issue of Rolling Stone has an excellent piece by Tim Dickinson titled The Machinery of Hope. The article takes a look inside the amazing grass-roots machine of the Obama campaign. You can view the web version of the article over at the Rolling Stone website.
I just received the issue in the mail this morning and took a look at the article. There are actually about 3-4 different articles on Obama in this issue, as well as another good piece by Matt Taibbi titled Hillary's Last Stand. If you are not a subscriber to Rolling Stone, you should go out and pick this issue up for some great reading.