An article from last February in Chicago Business News with some details about Obama's campaign logo, created by Sender: "Sender LLC landed the logo project through mo/de, a Chicago design firm working with AKP Message & Media of Chicago. Political consultant David Axelrod, who is working on Obama's campaign and worked on his 2004 U.S. Senate campaign, is a partner with AKP Message & Media."
Also, check out Logobama , a fan site where you can create your very own version of the logo. Here's also a DIY tutorial .
Widely praised, but not without it's share of controversy, of course: "Kind of amusing that Barack Hussein Obama’s campaign logo can be seen to feature both a crescent and a curved Islamic scimitar:"
Stage Design Magic as Propaganda Tool