I second the idea of a broker, but get an opinon from more than one. Im talking from experience, I wish we had got more than one persons opinion.
The bank pays them a % based on the loan you take out, and they have to discolse this information to you, so that you know they arent just telling you to take the loan that gives them the highest commission.
I have friends who'd recommend mortgage choice as a good option.

ETA: I agree with Shades, we've had 2 loans through westpac. the first one was approved within an hour of me faxing them the contract information on the phone.
The second time we went through a broker, and it took, without exaggeration, 6 weeks before we got our approval.