1. Check the voltage requirements: 110 V? 240 V? In the USA it's 120 V, for Australia it's 230 V, this means that a device rated to work 110- 240 V will work in both places and all you will need is to change the plug. For more information on the voltage requirements of different countries, check out this handy guide.
2. Get the right connections: If you are all set voltage wise and just need to change the plug don't get stuck buying a $40 converter. All you need is a small adapter, like this one, to change the plug and these generally run a mere $5 or less.
3. Go universal: Thankfully USB has made the world a lot smaller. Many small devices have the option of using either AC or USB for power. Use USB and save yourself the hassle of changing the plug and you're good to go. Another thing to look for is to swap out the figure 8 cord for the one appropriate to your region if you meet the voltage requirements. This is a more seamless solution than getting a plug adapter and these figure 8 cords are inexpensive and readily available all over the world.
(Images: Joelle Alcaidinho)