I have done the pre-approval application. Basically unlike other rebates where you pay for the item then get some money back afterwards, with the solar rebate you get approval before you make the purchase and the rebate money goes directly to the company supplying and installing the equipment.

I *think* you can get pre-approval by yourself and then find a company to do the work afterwards, but we have already got quotes for the work and chosen the company so we have done the application in conjunction with them (there are some techincal details that need to be supplied on the form that they have filled in). Not sure if I can give any other information about the process because we haven't got pre-approval yet.....other than we were advised the approvals are taking 12-14 weeks to be processed which is longer than the suggested time frame.
Oh also, it may be worth getting some one out to look at your roof/house because differents roof designs and orientations can vary in their suitability for solar panels. For example our roof is north facing but with a HUGE gum tree in front which shades the best north facing section So we are putting the panels on another section of roof but this limits how many panels will fit.