The SPI pins that you are looking for are labeled SSPX (where X = 2 or 5). The Edison module has 2 SSP (Synchronous Serial Port) interfaces (wikipedia: http://en.wikipedia.org/wiki/Synchronous_Serial_Port)
I have not used the SPI port yet in any of my experimenting. What language are you looking to program in?
Edit: The Edison module hardware guide indicates that there is only 1 SPI interface with 2 chip selects (see pages 14 & 16)
the guide refers to the Available SPI as SPI2 but the mini breakout schematic (and the fact that /dev/spidev5.1 is available) suggest that SSP5 is being used as the SPI interface, and SSP2 is useable for I2S
sorry for any confusion
Thanks a lot! That's very helpful. I am planning to use c to program the SPI port, where should I start to look into?