That Gizduino+ is a Sanguino clone. The SPI pins are on Digital pins D5, D6, and D7:
D5 - MOSI
D6 - MISO
D7 - SCK
and yes, level shift your pins. A simple resistor divider, as suggested, or you can use a 74HC4050 (CD4050 can be used if you can't get it locally).
connections using CD4050:
SD Card Pin----CD4050 Pin-----Gizduino+
CS--------------15 14-----D4
MOSI-----------12 11----D5
SCK------------10 09----D7
MISO----------------------------D6
the CD4050 connections can also be used with your Gizduino mini:
SD Card Pin----CD4050 Pin-----Gizduino mini
CS--------------15 14-----D4
MOSI-----------12 11----D11
SCK------------10 09----D13
MISO----------------------------D12