Another workaround is to change your Web Proxy (HTTP) to:

perth.cache.telstra.net

And the port to:

3128.

It works for me ... and has enabled me to see that, as at 4.02pm (Perth time), both the US and Australian AppleStores are down for an hour and being updated.

The new iPhone?
New Mac mini and iBooks?
New iPod Shuffles?
Asteroid?

Won't be long now! ;-)

And this hassle with Bigpond has forced me to learn more about my Mac and networking ... which is a good thing I suppose. :-)

RK