Leonidas:
ok thanks, and i also have an mp3 decoder... it also takes miso mosi and sck... does that mean that i can't hook both up at the same time?
The entire point of having slave select or chip select pins on a SPI bus is so you can have multiple devices on one bus. The answer is: yes you can.
Also
PaulS:
i can't hook it up to anything else?
Not if you want it to work.
This is not entirely true, you can bit bang SPI if you are desperate.
Please see this project, http://www.instructables.com/id/Music-Playing-Alarm-Clock/ , the SPI bus is connected to both a SD card and a MP3 decoder, it is probably the perfect example of what you are trying to do