
What the voice website says - Go to The Voice Facebook. Sign in, make sure you 'Like' The Voice Australia and click on the Vote Now tab and download the voting application. Facebook voting is free and, during the voting period, you can vote once a day for your favourite Artist.
What I say - I don't have facebook so I don't have much personal experience with this type of voting but to me it sounds pretty good. This is the only type of free voting you can use to vote for the voice and you can do it everyday. It might have a down side though. I wouldn't know
iTUNES
What the voice website says - During the voting period, if you purchase an Eligible Song (this week's Artist performance) via iTunes, it will contribute two votes to the Artist who performs the song. A maximum of ten (10) Eligible Song purchases, per Artist, by an individual iTunes user (constituting a maximum of twenty (20) votes per Artist) will be counted in the Vote Results.
What I say - Personally, this is my favourite way to vote. Since you get two votes plus the song for about 1.99 cents, or something around there. iTunes is easy to use but it can be easy to get carried away and waste all your iTunes money on songs you don't need or will never listen to. Set your self a budget before buying and you should be fine. I would also recomend buying the song once since buying it a couple times, really is a waste of money.
Good luck and keep voting to keep your favs in the competition.