Well, actually (http://www.kjp.id.au/archive/2005/10/22/anyhow.html), I can ring Australia.
Note to anyone out there: if you find yourself in China and can't ring home on your SIM card, try putting 1795100 infront of the country code, then number as usual. Apparently it works but at a slightly higher rate. (Better a higher rate than not working at all).
Now, if only I knew how much credit I had left....