'Frere Jaques' is a good one, so is 'Go and tell aunt Nancy' (well Nance is a town in France, does that count??), Au Claire de la lune is good too (in the silver moonlight, combing down her hair). Sorry I can't do the midi things, but you might try looking out for a book called the 'School Recorder Book 1' which has all those mentioned in, plus loads more. It's very British though you might be able to find a copy in junk shops or if you have a good friend here who could buy you one and send it over(I'm assuming you are not in the UK)... The old favourites like 'Twinkle twinkle' are good too, as it encourages children to listen to the tune and to learn to play by ear as well as by "dots".