"Joshua 'Schwa' Gargus" <schwa at cc.gatech.edu> replied:
	Why yes, of course :-)
	
	Select "objects (o)" from the World menu, click "Multimedia",
	and tear off an MPEGPlayer morph.  On it, click "Open", and 
	select your .mp3 file.
	
1.  Given that I can open movies and MIDI files from a FileList,
    I was expecting to play MP3s the same way.  I would never have
    guessed this.

2.  I tried this, and the result was "Error: a primitive has failed.:
    The primitive that failed was MPEGFile class>>isFileValidMPEG.
    This was in Squeak 3.2 #4952, and I have no independent way of
    checking whether the file _is_ a valid .mp3 or not, but it's
    certainly not plain text, whatever it is.

    The SqueakDebug.log didn't have anything illuminating in it; the
    path to the file is right, and all it says is that primFileValidMPEG
    failed, not _why_ it failed.

I have a Squeak 3.4 image?  Where do I find SqueakMap in it?