In Reply to: Telstra posted by gailo on Friday, 20. January 2012 at 16:57 Bali Time:
In your settings you will find and option to turn off data roaming. In the same spot you should be able to turn on wifi. This will stop your phone updating using Telstra data but you will still be able to receive messages and use the phone as usual, and connect to the internet via the many free wifi spots.
If you have problems finding this yourself most Telstra shops will be happy to help you.