The conversion rates from Australian Dollar ( AUD ) to American Dollar ( USD ), Euro ( EUR ) & British Pounds Sterling ( GBP ) at the moment are as follows...
$1 AUD = $1.03 USD.
$1 AUD = 0.78 EUR.
$1 AUD = 0.64 GBP.
So the conversion rate has no bearing on the pricing of Games, the price of games is based on the Regional Lockout.
For all video Games there is Regional Lockout, in other words a different code for a different country or Regional Area, which in turn affects the price.
Nintendo
Nintendo Entertainment System is region-locked. Regions are: NTSC (North America), PAL-A (United Kingdom and Italy), PAL-B (other European countries).
Sony
The PlayStation and PlayStation 2 consoles are region-locked.
The PlayStation 3 is region-free for PS3 games. There is only region locking for backwards compatible PlayStation and PlayStation 2 games, as well as DVD and Blu-ray Disc movies. Additionally, some games separate online players per region, such as Metal Gear Solid 4 Online. PlayStation Store only contains content for its own country, for example the UK store will not supply usable map packs for an imported US copy of Call of Duty 4.
The PS3 actually supports hardware region locking for PS3 games as well, based on Blu-ray Disc regions and a mechanism that allows for the game to query the model of the PS3,but as of current it is unused and all current region lockouts and separations are about online services.
Sega
Older Mega Drive games are region-free, but some new games can be region-locked (for example, Sonic 1 and Sonic 2 are region-free, but Sonic 3 is region-locked).
Microsoft
Xbox 360 is region-locked, however, a number of games are region-free and will play on a unit from any region, although it is up to the publisher if a game is region-free or not.
Some of the reasons for regional lockout are as follows:
Pricing
It is difficult to maintain a single pricing structure that can be applied worldwide. Region-locking a console means that there is no need for pricing parity across the world; different territories can have different prices for games without people simply shopping "wherever is cheaper".
Sensitive Regions
Some games could be regarded as offensive for religious or political reasons, and regional lockout may be required to prevent these games from being distributed in sensitive countries.
Staged Launches
If a console is region-locked, then staged launches of the games would be easier, as console producers could easily control the huge bow-wave of people wanting a game the moment it is released.
Piracy
Piracy is more common in some countries than others. For example it is particularly common in China as compared to North America. Region locks can prevent pirated games from these countries from being played on systems outside of their designated region.
So the the $60 Game pricing is restricted to America. I'm not the only one that wishes our games were only $60.