[Celtman]

There was no decleration of war against Iraq ...

      Indeed.

Did Congress declare war against Italy?

      Indeed it did.  Senate Joint Resolution 120, December 11, 1941.

Bulgaria ...

      Public Law 563, 77th Congress.  Hungary and Rumania: Public Laws 564 and 565, respectively.

[Destro]

Thanks - dare I ask Finland?

[annalex]

I have nowhere to confirm this on the Web, but I know that Bulgaria declared war on the US in the last months of its alliance with Germany in WWII. The Germans were pressing Bulgaria to declare war on the USSR, despite popularity of Russia there. Tzar Boris, instead, declared a purely nominal war on the US, -- which dropped all the unused bombs, intended for Roumania's Ploesti, on Sofia.

The USSR, by the way, did not hesitate to declare war on Bulgaria, despite its severing all ties with the Third Reich as the Red Army was on the north bank of the Danube.