During my trip in May I bought a sim card from the little store at the front of Matahari supermarket at Kuta square (beside the bookstore). Can't remember which brand but it has the sun with a smiling face printed on the sim card. They told me to do the following:
Dial 01016 61 2 then my number (landline) and I could speak to australia for Rp1000 per minute. Obviously 61 is oz and 2 is Sydney.
This worked fine with no delay and it was perfectly clear reception.
The cost was only Rp.1000 per minute
Hope this helps people.
Regards,
Dave