the process is:
talk to council and see what their subdivision requirements are for that particular address. each council is different so don't go by what anyone else says - talk to those with the info. examples of things you need to know are minimum block size you're allowed, minimum driveway width and minimum street frontage to allow subdivision (our area won't allow subdivision if street frontage less than 15m for the front block).
once you have a very clear picture of what council will allow (and it is allowable) talk to a surveyor. they will survey the property and draw up the plans for subidivision - including plans of installation of utilities.
you then have to submit da application to council and wait for approval.
then you have to contract out the utilities work (sewer, electicity, water etc). the sewer is the big one. for torrens title (which is what you want) only a mains pipe is allowed to cross a property - you can't have your personal sewer pipe cross another property to join into the mains. this means you may have to have the mains extended onto the second block (whether it be the front or back, depending on where the mains currently runs) and can be expensive.
once all work is done, utilities in, fence errected and signed off by council as complete, you then need to submit to the lands titles office for registration - your surveyor can do this for you. and again, you wait. once approval is given from lands titles (which can take several months) the you are free to sell.
it is a long process, with fees every step of the way - but - we have done three such subdivisions and they have all made us a tidy profit. this is not to say that "every" subdivision will make you a profit - you need to look at the selling value after completion, the cost of subdivision and initial purchase price, then do the numbers.
a rough guide of around $30-40k is about right - depending on how far the utilities have to run from their present position - might be less, might be more.
oh - and don't forget to get phone cabling put in the ground while trenches are open.
hope this helps