ibook g4 running 10.4.11 will not find my iphone ?

I have just bought this ibook g4 running 10.4.11 but i cant download latest version of itunes and the itunes what is on it will not conect to my phone well saying that i did get it to conect once but it would not let me do anything i have read that i need to update to 10.5.8 but when i click search for updates it says all programes are uptodate i am new to using apple mac so could any 1 help me please with some easy to understand info thanks.