Hello i was wondering if the Seeeedstudio Sim900 GSM use the Spi Pins or just Straight Rx and TX? I need to add some Leds to my arduino project and all over pins are taking besides D10 - D13 in case they are taking? Can someone please help me out?
Thanks
After 776 posts I would have thought that you'd know to include a link by now! 
Ut oh I'm sorry forgot a link you are rightmy fault http://www.seeedstudio.com/wiki/GPRS_Shield_V1.0 all i know it uses D7 and D8 for software serial and D9 to power up the network that is all i have seen so far wasn't sure if it uses the Spi D10 though D13 pins not not and I'm running a Uno board.
From that page:
Pins usage on Arduino
D0 - Unused if you select software serial port to communicate with GPRS Shield
D1 - Unused if you select software serial port to communicate with GPRS Shield
D7 - Used if you select software serial port to communicate with GPRS Shield
D8 - Used if you select software serial port to communicate with GPRS Shield
D9 - Used for software control the power up or down of the SIM900
Note: A4 and A5 are connected to the I2C pins on the SIM900. The SIM900 however cannot be accessed via the I2C .
So you can quite freely use D10 onwards without conflicting with the shield.
Okay thank you.