Question about AU services. :)

Hey all, there is a chance that I will be relocating to Austrailia from the US in the near future. I have some questions about how Cell Service works down there.

I have looked up on some prvidors sites and since I am not really used to the way they price plans and how things work down there, I am just not getting it.

The plan I am on now is a T-Mobile unlimited talk, text, messaging, data. It's an individual plan.

My other plan is an AT&T Family Plan with 1500 Minutes and rollover. Some phones have Data, some don't. All have unlimited messaging and the ones with data have Unlimited Data (yay for being grandfathered in).

Basically, I want to know what it will take to get a family plan with a good pool of minutes (if they offer them), messaging and data. Data does not have to be unlimited, but would be nice to have a high limit as well as a high to unlimited messaging plan.

Do they have plans that include unlimited mobile to mobile for people on the same network or family plan?

How do these minute pools work?

I know it's a lot of questions, but this one is something I hope to get sorted out.

Thanks in advance for any advice or any answers you can provide.