I'm pretty sure you just get a burst of clock pulses with the command
SPI.transfer(value);
SPI.begin is like Serial.begin - nothing actually goes on until you command a read or a write.
The Dataout will come out of the MOSI pin and be read back on the MISO pin. The same burst of clock does both I believe (I have only written out).
http://www.arduino.cc/playground/Code/Spi
here's an example of data going out:
number_to_display = number_to_display | colon; // OR in the decimal point
digitalWrite(SS,LOW); // take the SS pin low to select the chip
SPI.transfer(minutes_tens_address); // select the Address,
SPI.transfer(number_to_display); // select the data
digitalWrite(SS,HIGH); // take the SS pin high to de-select the chip