SPI communication ??

does any one can help me to understand how to buid a SPI communication routine?
I would use a AD7731 24 bit DeltaSigma ADC with a PIC16F876, the AD7731 use a SPI interface both for 8 or 16 bits configuration register and for 24 bits data word.
Fist of all is possible to communicate via SPI with AD7731 as it use 8,16 and 24 bits data words?
I suppose yes, and I can do it?

Thanks

I2CRead and I2Cwrite commands could be usefull to communicate with the ADC?

or SHIFTIN, SHIFTOUT coul be more appropriate?

Hello. If you need SPI communication use SHIFTIN / SHIFTOUT command.