Score! (assuming you mean the orchestral piece at 3:10 and not the oom-pah-pah that comes before/after it) it's the Prelude to Act III Of Lohengrin, by Wagner. I knew it was Wagner, but it took me a while to pin it down...
I was listening to Help! the single at first, didn't know you meant the soundtrack album. Boy, Wagner really knew how to use a tuba, didn't he?