audacity on the mac works!
open the file in audacity (it's free... google for it, windoze version also)
select the whole file
goto the effects menu and choose "Change Tempo"
decide how slow you wanna go- click preview to hear a snippet
click "OK"
export your file to another mp3 (or wav or whatever) so it will play on your player. audacity has it's own saved file project structure you can only play in audacity.
you can trim off the parts you don't need, or export only the slowed down selection, so that you only save the riff or lead you want. easier to repeat to listen and practice. rock on!