I found a Freeware program, "Midi Typer", which is very useful for MIDI
files received as an e-mail attachment on the Macintosh.  It peeks into
any suspected MIDI file, and if indeed it _is_ a MIDI file, "Midi
Typer" sets Type and Creator in the Mac file directory to match your
favorite MIDI sequencer program on your computer.  The icon of a file,
or a folder or entire disk drive, may be dragged on top of the Midi
Typer icon to launch the process automatically.

The Midi Typer program may be down-loaded from URL

  http://rhythm.harmony-central.com/~ftp/software/mac/midi/midi-typer-104.hqx

Robbie Rhodes