err... you can do this in Internet Explorer 7
open your temp internet files,
sort by date last accessed,
find a song you want on myspace & add it to your own profile,
now view your own profile, and listen to the song.
Got back to the temp files window, hit f5, and there is your mp3...
has a silly obfuscated name, but one quick copy & rename later and you have your file
not really rocket science, and taking mp3s of myspace is definitely not confined to safari, or osx.