I've just got another snippet of information for any of you doing DCF through Sydney who already have packet 3 in your hands -- this might just be AussieDude and myself, but I thought I'd post in case there's anyone else.
I previously posted that the Consulate in Sydney told me to go ahead and send in forms DS-230 parts 1 & 2 and DS-2001 (if we were ready) prior to my husband filing the I-130. Well, I went ahead and sent in DS-230, and it promptly got returned to me (with no explanation, mind you). After some more emailing with Sydney, we've now been told that if you already have packet 3, you can't file any of the forms until the I-130 has been filed. But you can still go ahead and get the forms ready, get your medical etc.
This shouldn't add any extra time to the process, as I can submit my forms on the same day my husband files the I-130, but just wanted to let you know so you don't waste money on postage!