Regarding the tax rebate and childcare benefit:
Childcare benefit (CCB) is the amount that the government pays of your fees. This is based on your combined family income and the amount of discount you get varies accordingly. The discount is taken off your fees and you pay the difference (gap). Depending on your income and your centres fee schedule you might pay from as little as $8 per day up to the full fee amount.
If you pass the test from centrelink - you may be elligable to receive the 50% tax rebate at the end of each 1/4. To qualify usually means both parent sare working, or studying. You might qualify if you do the study you mentioned. This 50% is above the CCB that centrelink already pays. It is 50% of the part (gap) that you pay. So if you pay $20/week for care and you qualify, at the end of the quarter you will get $10/week back - usually paid into your bank account.
You will need to contact centrelink about your child attending care - if you get a family payment from them you can set this up over the phone, if not you will need to fill out paperwork, so do this well in advance. Depending on the centre you choose and whether they are using the new CCMS (childcare management system) you may need their CRN (childcare reference number) to link your child to their service - so you will need to choose a centre bfore doing this.

Regarding centres, don't just ring, you won't get a good idea of quality, etc without actually going in for a tour. All directors should be happy to do a tour any time of the day (be suspicious if they appear reluctant - what are they hiding or embarassed about), I personally (being a director) happily do tours, though lunchtimes and rest time are tricky - if I am relieving other's lunches, etc. I phone call to arrange a time would be a good idea too.
Depending on where you are, there may well be a waiting list, so start looking now, the good ones probably will have lists unless you are in a quiet area (like me).

Hope I've answered some of your questions - anything else, just ask!