We try songs with actions (he's a big fan of the head-shoulders-knees-toes song) and signing; he seems to be more attatched to the tunes of a song than the words (which makes me think he's probably got some kind of inherent musical talent; I'm sure he'd love your instrument collection).
(That reminds me. You wanted me to look at something next time I went to Lark in the Morning - I'm going down there next week to see about the kiddo's birthday gift, but I don't remember what it was you wanted me to look at. Refresh my memory, please? :-))