I just thought I’d post a link to an Australian broadband speed test site I found:
It appears to work very well, and has links to a number of mirrors run by ISPs and web hosts. So, chances are, if your ISP is in the list you can conduct a test without actually adding to your usage. 
I’m using Internode, and I moved us onto a new plan the other day. We unfortunately can’t get ADSL2, but our new speed is, I must admit, very nice:
Test run on 04/07/2007 @ 08:44 PM
Mirror: Internode
Data: 15 MB
Test Time: 20.39 secsYour line speed is 6.15 Mbps (6146 kbps).
Your download speed is 768 KB/s (0.75 MB/s).
Mmmmmmmm.
Tried it and it does work pretty well. Gives me results consistent with some of the other top-end speed tests.
Another one I really like is http://www.howzippy.com. I just checked it against the ozspeedtest result, and it’s pretty much spot on.