During WWII, two soldiers (Charlton Heston and Harry Guardino) are sent on a secret mission in Nazi-occupied Rome. However, the organized resistance they are told to make contact with doesn't really exist--it's just a couple pathetic souls. So, the two soldiers just hide out in the city--making note of the German forces and sending messages back to headquarters with homing pigeons. There's MUCH more to the film than this, but I don't want to give too much of the plot to you--in case you haven't seen it.
While the above sketchy outline doesn't sound the least bit funny, the film is very much a tongue in cheek comedy. LOTS of complications develop as well as romance. The bottom line is that the film is a decent light comedy--the sort of thing they began making in the 60s and 70s--once memories of this god-awful war began to fade. A cute but slight story worth your time.
By the way, the Irish priest (Arthur Shields) might well remind you of Barry Fitzgerald by his look and performance. Well, that's because despite the different stage names, Shields WAS Barry Fitzgerald's brother! Also, while a small role, I loved Rudolf Anders' performance later in the film. Seeing this German commander losing his mind was HIGHLY entertaining and his phone conversation was the best part of the film.