code exemple for control pga2310 via sony ir

hi all i have an arduino dumilanove and i found code for sony ir protocol on this site its working good.the code return the key number of my remote on serial monitor.how to control pga2310 volume controle with my remote. anybody have exemple code to comuniquate spi with pga. iam good in electronics but not realy on programming i am lost. thanks.

ps...sorry for my bad english my primary language is french :-[