I just shipped a board (8'2) from Melb to Newcastle.
The problem I had was that most of the major carriers like TNT require you to have an account number (for businesses etc).
I ended up using smart send, which basically act like a broker, and TNT got the job.
It cost $205 which included $1800 worth of insurance.
Sending boards (or anything via post) is like a lottery, it doesn't really matter which freight company you choose.
Nine out of ten times it will arrive safe and sound, but it only takes one link in the chain, (one grumpy courier who hasn't had his morning coffee) to trash your board.
Make sure you pay for the insurance.
www.smartsend.com.au/