How to register company in Australia

Hi,

You guys are from Australia.
Hope i could get few info from you.

How to register company in Australia,
and which city has better tax rate or less expense to start with.

Deals mostly in IT web projects.

My family relatives coming to Australia as they got PR.

if someone guide me good recruitment agency dealing with IT resources. ( One is project manager with Ernest & Young - E&Y, and another with C#, .Net developer/Team Lead with Australian MNC here.

-what is normal tax rate on business
and income tax

-what is salary average for marketing people there ?

If you are able to answer will be thankful.