Last year on Anzac Day 2006, I was privileged to have been invited by some Aussie Vietnam War veterans to take part in some Anzac Day ceremonies in Sydney associated with that patriotic day. In doing so, as a USAF veteran, in the Commonwealth tradition, I wore some of my service ribbons on my suit jacket pocket and displayed small crossed Australian and U.S. flags above the ribbons. I also wore my American Legion Post cap. The Anzac Day parade in Sydney is a wonderful thing to see! You'll never hear so many marching renditions of "Waltzing Matilda" played by so many different parade marching band groups as you will see at the parade.
You are staying at a great hotel for viewing the parade. You can drill down to see the Sydney Anzac Day particulars here:
http://www.rslnsw.com.au/index.cfm?page=450