i switched to lyca mobile assuming i could get free internet, their website lists iphone as a compatible device for internet, but upon calling them i am informed they dont support the device.
so heads up dont use them at all costs. i have contacted the accc about this issue.
You probably can use it with iPhone, but it needs to be unlocked/jailbroken so you can change your APN.
There is a service which can do this for you without jailbreaking/unlocking that I read about on whirlpool.