I don't know about on the internet, but any halfway decent record store will have a copy... usually along with the rest of "The Magic Flute, " the opera from which it is taken...be aware though, that there are several (hundred!!) versions out there, so if you know which conductor/orchestra played the version you've heard and liked, ask specifically for that one... obviously each version has the same notes, but Herbert von Karajan conducting the Prague sounds very different to Simon Riddle and the Philly, or Georg Solti and the bayerischen...