Unwired looks good, basic plan is $35, and all their plans are capped -
http://whirlpool.net.au/article.cfm?id=1298&show=all
Now if the unit was smaller, didn't need a $ 99 battery that lasts no more than an hour if you want to use it away from the powerpoint and if it had better coverage of nathan's area it would be really neat. According to this
map nathan's place might just be covered -
I'm not sure what side of the road he is on, so it's hard to say.
There are planning on offering VoIP with it, so it would be cool to use that instead of Telstra copper. Although I've just upgraded to 1.5/256k, and if iiNet upgrades my exchange I can get much faster uploads than that even.