Well if you're at home then use your phone's Wi-fi connection, although that's still not going to be unlimited like in the EU. Perhaps instead of your phone then you'll need to use skype on a netbook.
Small additional point. Who will you be talking to for 6 hours a day? Friends in the EU on internation rate (although vodaphone have a $2 for an hour rate) who are asleep, or friends in NZ that you've not got yet and due to the phone charges certainly won't be accustomed to talking for long times on mobiles. Local landline calls are generally 'free', so perhaps a cordless landline would work, subject to making friends quickly.