Interested to hear how you get on..
At work and wife was out so will have to pick up my parcel tomorrow!
10/01/11 13:46 Attempted delivery - Item carded and transferred to Post Office for collection
10/01/11 13:17 Awaiting Collection From Post Office
10/01/11 12:24 Attempted delivery - Item carded and transferred to Post Office for collection
10/01/11 11:34 Onboard with driver
10/01/11 07:11 Received for processing
09/01/11 14:31 Scheduled for delivery
02/01/11 14:06 Received and awaiting clearance for delivery - stuck at customs
14/12/10 09:52 Processed - enroute to final destination
14/12/10 09:50 Received and ready for processing
13/12/10 16:18 Item lodged
I emailed Customs after reaching a letter from them and explained that the cards posted was from my personal collection over a period of time, even though I declared them to be in excess of $1000 (they are PRE-OWNED) and I have EXPORTED them to BGS for grading (paid for) and I opted for $2000 for INSURANCE PURPOSES ONLY.
My supporting documentation to demonstrate proof of exporting:
1) Proof of exporting of my basketball cards to the United States – via receipt from Australia Post / Express Courier International delivery slip dated 18 Nov 2010 – keep this slip!!!
2) Tracking summary from both Australia Post and USPS – label receipt number – ED xxxxxxxxxx AU as per Australia Post receipt – use USPS website Track and Confirm and Australia Post Track and Confirm.
3) The Beckett grading order form with the list of cards to be graded and some of the pictures of my basketball cards to be graded with a total of US$224 payable to Beckett Grading Services for grading services + return postage and insurance.
4) My credit card statement showing that I have paid US$224 for the grading services + return postage and insurance dated 01 Dec 2010 and $112 at Australia Post dated 18 Nov 2010.
5) Beckett grading report (which Beckett will email you of what grades you got for your cards) and that they have posted the parcel on 13 Dec 2010.â€
So yeah - it worked for me!

/ p.s - I'm not responsible if your > $1k package does not pass through customs!
For me - lessons learnt - if you want it quick to the USA - use UPS / Fedex etc and don't send it during the silly season! Mine was posted in mid-Nov, opted for the 10 business days deal.
If posting using Australia Post, I believe any packages to US weighing 453g (~ 1pound) will cost you extra A$9 and takes another 48 hours to clear - new security measure because of the mail bomb scare a few months ago.