im not... heres what im doing... im using an atmega644p for the main board... its using the sanguino bootloader to interact with the arduino firmware, from there i have hooked up 8 buttons connected to a piso shift register and that to the 644p, i also have a 5 pin monochrome lcd screen hooked up to the 644, i wanted to have a way to read files from an sd card, be able to display the names on the screen and also play them, i bought the sd card breakout board from cutedigi.com
http://www.cutedigi.com/product_info.php?products_id=4435&osCsid=c21092b55ad5435c2977d2a70293fe28
and a vs1003 mp3 decoder breakout board from cutedigi.com
http://www.cutedigi.com/product_info.php?products_id=4343&osCsid=c21092b55ad5435c2977d2a70293fe28
and i figured out that im going to need more than one set of spi pins so i decided to add another arduino, i was thinking of reading the sd card data with one, sending the undecoded data to the 644p via serial and from that have the mp3 decoder hooked up and send the raw data to the vs1003 to be decoded and played
so i wanna know:
- if you can send raw data like that using serial
- if you can read files with unknown names from the sd card using the arduino library
- how to work with the vs1003
- if there is an easier way to do this =)
i appreciate the help and the concern guys! thanks 
edit: oh and thanks for suggesting rogue robotics board, but i had seen it before and its a bit too big and too expensive for this project