Happy to!

It's an app from Smule, called mini Magic Piano. Recently it's been free & comes with some music. Weekly, a few more pieces of free music are there which you can download. I've not used it on iPod touch, but it adverts as working on 3rd generation.

It works by dropping notes for left & right hand, spaced where keys would be, & dropped close or far apart to work as a quarter-note, whole note etc. It helps a lot if you know what the piece is supposed to sound like . You can set it so that, even if you don't tap the exact note, the right note plays (my choice).

Only my cats get to hear me & it's very relaxing & fun.