'Volare' Lawsuit -- Okay, Everybody ... Vooo Lar Eh ......

"Volare" -- the Italian song made famous by Dean Martin -- is the centerpiece of a nasty legal battle ... and it will determine who gets to sing it ... and where.

You know the song -- Voooo lar e oh oh oh oh ....

Part of the fight is over who controls the rights to the American version -- the music publisher or the family of the guy who co-wrote it when it was first recorded in Italy in 1958.

There's a lot at stake ... "Volare" is still a big hit -- and not just in karaoke bars. There've been at least 40 different covers -- from artists like Frank Zappa, Paul McCartney, and David Bowie.

And whoever owns the song will have the power to decide who can record it.