As per the rest of the world (it seems) address 2 isn't always used. Though as I life in a flat, some of mail is in the form:

Unit xx
yy My Street

instead of the more usual "xx/yy My Street"

Post codes are always 4 digits.
Phone number are anything from 6 to 10 digits. 6-digit ones (starting with 13) are for companies and info services and the like. Residential are 8 digits, with a 2-digit state prefix if you're ringing another state. Mobile phone number are 10 digits.

Oh, and state abbrevitations have two or three letters. It makes it easy to spot the direct mail companies that use inflexible American software when you see NS instead of NSW on the envelope :)

There are probably a number of exceptions to the above rules but that's about as pedantic as I'm going to forget, and you may well all be asleep by now anyway :)