I believe that DU is only used for armor-penetrating rounds such as on the A-10's GAU-8/A, not for any kind of explosive bombs that I've ever heard of (it's purpose is to enable dynamic armor-piercing rounds to penetrate metal better). As such, DU is totally irrelevant to this discussion as far as I can tell (I'm no expert but my dad used to work with the A-10 as an Aeronautical Engineer for Republic Fairchild - I'll try to get more info from him).
The Navy and Army also have some DU munitions, but certainly not in the kinds of weapons that would have been used from the air against Saddam's presidential sites in the attacks in question.
Thanks for the info.
Thanks for the information regarding Depleted Uranium, this will clarify some issues here.