I recently purchased a musical effects unit from America which over there it requires a power pack that has a 110v input and an output of 9vac (voltage alternating current) 1000mA. Is America run off AC or DC?

Now i live in Australia where we have 240v AC mains power. I need to reproce those above settings. If i purchased a voltage down-size transformer to go from 240v to 110v then plug the power adaptor off the transformer into the Effects unit, would this work?
America runs on AC power. As far as the step-down converter, it should work. I've been doing the same thing you described with my laptop computer since I moved to England with no problems, so it should work for the effects unit. However, you probably wouldn't want to have it plugged in constantly, because if you burn out the transformer your unit is completely screwed.
We are AC and the power pac converts 110V AC to 9V DC.

I'm pretty sure you sould be able to find some 220V AC to 9V DC Adaptors there which would probably be cheaper and easier.
Ibanez, he has a 9VAC adapter. I have several things that run off 9VAC. Not everything is DC.

A stepdown from 240 to 120/110 will work.
Internally the pedals are the same everywhere they just sell a different adapter in different markets. Internally amps are the same to but the power supply changes for different markets something not so easily swapped as a wall wart.