If you can send him wav or aiff files, those can be imported into garageband. I think MP3 files are converted to aiff files for import. I think you only export from GB as aiff, but iTunes can then convert as needed.

When you send the files back and forth, just make sure you have some kind of "click count-off" at the beginning of every track so you can line them up. Some of these tracks might have a count off, a minute of silence, then some music, and so on.

Kevin


Now at bandcamp: Crows Say Vee-Eh @ bandcamp or soundcloud: Kevin @ soundcloud