>Is there any portable MP3 player that has interface to MCU,
>e.g. RS232? If not, could anyone suggest me some ways to achieve
>the purpose, whatever device or method is not important, I only
>need to provide a solution that a user can listen to music when
>he/she is walking and the track is selectable by a PIC (i.e. programmable).

Oh, you mean you are making one of those devices that give a context related 
commentary when walking around a historic site? 

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