Hmm. I'm vaguely thinking of making a mix called "The War on War" combining pro- and anti-war songs. I'm anti-war myself, but I figured the conflict would make this mix more exciting. ... Are you looking for songs protesting this war in particular, or also other wars or war in general? For the Iraq war in particular, maybe the best song I've heard in response is Robert Wyatt's "Lullaby for Hamza" from his 2003 album, Cuckooland. Tom Waits's "Day After Tomorrow" is one you might hear a lot about, though it's not really specific to the current war even though it was written in response to it. ... Is "Rockin' In The Free World" really a war protest song? I'm surprised you didn't pick something from Neil Young's latest album instead, I mean, at least considering your username and all....

Edwin Starr's version of War is a classic. Great theme. Barry McGuire's Eve of Destruction, Marvin Gayes' Whats Going On, Bob Dylan's Hard Rain, Peter, Paul and Mary's If I Had A Hammer and Woody Guthrie's This Land Is Your Land are all classic protest songs that may or may not fit into your intent. As abangaku pointed out Neil Young's latest has Let's Impeach the President and others that may fit. Peace....

Two solidly seething songs about BushCo from The River In Reverse by Elvis Costello and Allen Toussaint: "Broken Promise Land" ("In the name of the father and the son, in the name of gasoline and a gun...") and "The River In Reverse"("Count your blessings when they ask permission to govern with money and superstition, they tell you it's all for your own protection 'til you fear your own reflection").

Ted Leo and the Pharmacists have a number of good ones, particularly "Bomb Repeat Bomb", "Shake the Sheets", and "The One Who Got Us Out". Pearl Jam has the mediocre but unobtuse "Bu$hleaguer" and the preferable "Insignificance". I'm in favor of the war myself - in theory, at least - but I'm not the type to look down on its critics. Good luck!