Simple really, I picked up a 3DS in the US because of the immense price differences, but live in Australia. Wondering if I can get away with buying a $10 plug adapter without a transformer in it that will still send 240 V into the US charger, or if I need to cough up god-knows how much to Nintendo for a local charger? I know Apple's stuff for example will handle 240/110 V without any trouble, but not sure about the 3DS.
There's usually a little bit of text on the side of the charger that lists its operating voltages. The best idea is to go by what's written on the charger, lest you find yourself with a different model than someone else's and end up frying something based on bad advice.
Consensus on the internet is that the US charger runs on 110v, and can't take 240v. However, you should be able to buy a charger locally (probably from a used game shop, if you've got one local) and it should put out the same output voltage with the same power connector. It's probably not worth getting a step-down transformer, since it's going to weigh a ton and introduce a bunch of unnecessary components to the equation.
This is kind of a bummer - I think they did the same thing with the DS. When I travelled to Europe it was the only device that would NOT take European line voltages, so I had to travel to a shop in the Netherlands to pick up a replacement. Even then, I don't think I paid more than 10 Euro for it.
Any standards-compliant (UL, CE, CSA, etc.) AC/DC converter will list the voltages (e.g. 100-240 V) and frequencies (50/60 Hz) it accepts.
If it won't take what you have available, there seem to be many chargers available that are universal, though I'm unsure of their availability in Australia.