Be careful with Optus data as it's my understanding that they exclude VOIP and such protocols from their data caps.

Viber is better than Skype for call quality and you do have to keep the app open to receive calls.

Ensure that you use them on Wifi connections NOT 3G.

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[COLOR=Black]Liberty GT Spec B tuned 240 HP & 372 Nm at the hubs.[/COLOR] "Instead of banning high performance cars - ban low performance drivers"