For video games there are three basic gaming regions... (there are a few more like Korea and China but those are most likely irrelevant for importers in the west).
PAL - Europe, Australia (Often consoles in Africa have this region though it isn't an official region) NA - North America, Mexico (Probably further south as well). JPN - Japan nuff said.
This game which I'm playing was released in Europe (PAL) If you are in Australia, it will function.
These regions only apply to REGION-LOCKED consoles however... (And even locks can be gotten past... or I wouldn't import at all). The Wii is region locked but the DS, PSP, PS3 (only PS3 games) are not. The 360 is selectively region locked, it depends on the game. --- Get, Play The Undersold Triforce: Z+W, NMH, Okami! PM of the SSR Board + Ninja of SATBK/SATFS forever
To be more specific to the question... It will work on the Aussie Wii if it is the PAL version 100% guaranteed. It never released in the US, only PAL and JPN releases (the PAL version has JPN voices and Funimation voices).
If you wanted to, it could be anything from very cheap (having to buy a single SD card) to priceless (already have the SD card) to make your Wii accept all regions if the US takes something you never/later get. --- Get, Play The Undersold Triforce: Z+W, NMH, Okami! PM of the SSR Board + Ninja of SATBK/SATFS forever