There's an application note on Microchip's website about playing MP3 with dsPIC, so I may be investigating that! It uses an external VLSI MP3 decoder, and a serial RAM chip for a buffer.
I compiled this on my PowerPC MAC, and it runs, but I get an error, I previously upgraded the bootloader using the old python loader script. Here's what happens on my BPv3:
Parsing HEX file [BPv3-Firmware-v4.1.hex] Found 21503 words (64509 bytes) Fixing bootloader/userprogram jumps Opening serial device /dev/cu.usbserial-A7004E19...OK Configuring serial port settings...OK Sending Hello to the Bootloader...OK